diff --git a/.github/workflows/infra_tests.yml b/.github/workflows/infra_tests.yml
index 28aa56d3365e..98a5b91fbf06 100644
--- a/.github/workflows/infra_tests.yml
+++ b/.github/workflows/infra_tests.yml
@@ -25,13 +25,6 @@ jobs:
           sudo env "PATH=$PATH" pip install -r infra/ci/requirements.txt
           sudo env "PATH=$PATH" pip install -r infra/build/functions/requirements.txt
 
-      - name: Install python-apt
-        run: |
-          git clone https://salsa.debian.org/apt-team/python-apt.git -b 1.6.5ubuntu0.3 --depth 1 /tmp/python-apt
-          cd /tmp/python-apt
-          sudo env "PATH=$PATH" apt build-dep ./
-          sudo env "PATH=$PATH" python setup.py install
-
       - uses: GoogleCloudPlatform/github-actions/setup-gcloud@master
         with:
           version: '298.0.0'
diff --git a/.pylintrc b/.pylintrc
index 3b764856a5cb..02abe5f6c1f8 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -90,6 +90,7 @@ disable=print-statement,
         reduce-builtin,
         standarderror-builtin,
         unicode-builtin,
+        xrange-builtin,
         coerce-method,
         delslice-method,
         getslice-method,
diff --git a/infra/base-images/all.sh b/infra/base-images/all.sh
index f5ac04752809..6d012d5aa1ab 100755
--- a/infra/base-images/all.sh
+++ b/infra/base-images/all.sh
@@ -20,5 +20,3 @@ docker build -t gcr.io/oss-fuzz-base/base-clang "$@" infra/base-images/base-clan
 docker build -t gcr.io/oss-fuzz-base/base-builder -t gcr.io/oss-fuzz/base-libfuzzer "$@" infra/base-images/base-builder
 docker build -t gcr.io/oss-fuzz-base/base-runner "$@" infra/base-images/base-runner
 docker build -t gcr.io/oss-fuzz-base/base-runner-debug "$@" infra/base-images/base-runner-debug
-docker build -t gcr.io/oss-fuzz-base/base-sanitizer-libs-builder "$@" infra/base-images/base-sanitizer-libs-builder
-docker build -t gcr.io/oss-fuzz-base/msan-libs-builder "$@" infra/base-images/msan-libs-builder
diff --git a/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper.py b/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper.py
index 6b4327c10e5c..04aa4207c055 100755
--- a/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper.py
+++ b/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 ################################################################################
-"""Wrapper script to call clang or GCC with modified arguments."""
+
 from __future__ import print_function
 import os
 import subprocess
@@ -26,23 +26,23 @@
     '-aux-info',
 ]
 
-M32_BIT_ARGS = [
-    '-m32',
-    '-mx32',
-]
-
 
-def invoked_as_gcc():
+def InvokedAsGcc():
   """Return whether or not we're pretending to be GCC."""
   return sys.argv[0].endswith('gcc') or sys.argv[0].endswith('g++')
 
 
-def is_32_bit(args):
+def Is32Bit(args):
   """Return whether or not we're 32-bit."""
+  M32_BIT_ARGS = [
+      '-m32',
+      '-mx32',
+  ]
+
   return any(arg in M32_BIT_ARGS for arg in args)
 
 
-def filter_wl_arg(arg):
+def FilterWlArg(arg):
   """Remove -z,defs and equivalents from a single -Wl option."""
   parts = arg.split(',')[1:]
 
@@ -55,7 +55,7 @@ def filter_wl_arg(arg):
 
     if part == '--no-undefined':
       continue
-
+      
     filtered.append(part)
 
   if filtered:
@@ -65,29 +65,29 @@ def filter_wl_arg(arg):
   return None
 
 
-def _remove_last_matching(args, find):
-  for i in range(len(args) - 1, -1, -1):
-    if args[i] == find:
-      del args[i]
+def _RemoveLastMatching(l, find):
+  for i in xrange(len(l) - 1, -1, -1):
+    if l[i] == find:
+      del l[i]
       return
 
   raise IndexError('Not found')
 
 
-def remove_z_defs(args):
+def RemoveZDefs(args):
   """Remove unsupported -Wl,-z,defs linker option."""
   filtered = []
 
   for arg in args:
     if arg == '-Wl,defs':
-      _remove_last_matching(filtered, '-Wl,-z')
+      _RemoveLastMatching(filtered, '-Wl,-z')
       continue
 
     if arg == '-Wl,--no-undefined':
       continue
 
     if arg.startswith('-Wl,'):
-      arg = filter_wl_arg(arg)
+      arg = FilterWlArg(arg)
       if not arg:
         continue
 
@@ -96,11 +96,11 @@ def remove_z_defs(args):
   return filtered
 
 
-def get_compiler_args(args, is_cxx):
+def GetCompilerArgs(args, is_cxx):
   """Generate compiler args."""
   compiler_args = args[1:]
 
-  if is_32_bit(args):
+  if Is32Bit(args):
     # 32 bit builds not supported.
     compiler_args.extend([
         '-fno-sanitize=memory',
@@ -109,7 +109,7 @@ def get_compiler_args(args, is_cxx):
 
     return compiler_args
 
-  compiler_args = remove_z_defs(compiler_args)
+  compiler_args = RemoveZDefs(compiler_args)
   compiler_args.extend([
       # FORTIFY_SOURCE is not supported by sanitizers.
       '-U_FORTIFY_SOURCE',
@@ -122,15 +122,15 @@ def get_compiler_args(args, is_cxx):
       '-fno-lto',
   ])
 
-  if invoked_as_gcc():
+  if InvokedAsGcc():
     compiler_args.extend([
-        # For better compatibility with flags passed via -Wa,...
-        '-fno-integrated-as',
+      # For better compatibility with flags passed via -Wa,...
+      '-fno-integrated-as',
     ])
 
   if '-fsanitize=memory' not in args:
     # If MSan flags weren't added for some reason, add them here.
-    compiler_args.extend(msan_build.get_injected_flags())
+    compiler_args.extend(msan_build.GetInjectedFlags())
 
   if is_cxx:
     compiler_args.append('-stdlib=libc++')
@@ -138,36 +138,35 @@ def get_compiler_args(args, is_cxx):
   return compiler_args
 
 
-def find_real_clang():
+def FindRealClang():
   """Return path to real clang."""
   return os.environ['REAL_CLANG_PATH']
 
 
-def fallback_to_gcc(args):
+def FallbackToGcc(args):
   """Check whether if we should fall back to GCC."""
-  if not invoked_as_gcc():
+  if not InvokedAsGcc():
     return False
 
   return any(arg in GCC_ONLY_ARGS for arg in args[1:])
 
 
 def main(args):
-  """Modify arguments and call the real compiler."""
-  if fallback_to_gcc(args):
-    sys.exit(
-        subprocess.call(['/usr/bin/' + os.path.basename(args[0])] + args[1:]))
+  if FallbackToGcc(args):
+    sys.exit(subprocess.call(['/usr/bin/' + os.path.basename(args[0])] +
+                             args[1:]))
 
   is_cxx = args[0].endswith('++')
-  real_clang = find_real_clang()
+  real_clang = FindRealClang()
 
   if is_cxx:
     real_clang += '++'
 
-  args = [real_clang] + get_compiler_args(args, is_cxx)
+  args = [real_clang] + GetCompilerArgs(args, is_cxx)
   debug_log_path = os.getenv('WRAPPER_DEBUG_LOG_PATH')
   if debug_log_path:
-    with open(debug_log_path, 'a') as log_file:
-      log_file.write(str(args) + '\n')
+    with open(debug_log_path, 'a') as f:
+      f.write(str(args) + '\n')
 
   sys.exit(subprocess.call(args))
 
diff --git a/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper_test.py b/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper_test.py
index c97ecfe76a34..a05592d38bce 100644
--- a/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper_test.py
+++ b/infra/base-images/base-sanitizer-libs-builder/compiler_wrapper_test.py
@@ -1,19 +1,3 @@
-#!/usr/bin/env python3
-# Copyright 2020 Google LLC.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#        http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-################################################################################
 """Tests for compiler_wrapper."""
 
 from __future__ import print_function
@@ -24,41 +8,35 @@
 
 
 class CompilerWrapperTest(unittest.TestCase):
-  """Tests for compiler_wrapper."""
 
-  def test_filter_z_defs(self):
-    """Reference tests for remove_z_defs."""
-    self.assertListEqual(['arg'],
-                         compiler_wrapper.remove_z_defs(['arg', '-Wl,-z,defs']))
+  def testFilterZDefs(self):
+    self.assertListEqual(
+        ['arg'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z,defs']))
 
-    self.assertListEqual(['arg'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', '-Wl,--no-undefined']))
+    self.assertListEqual(
+        ['arg'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z,--no-undefined']))
 
-    self.assertListEqual(['arg', '-Wl,-z,relro'],
-                         compiler_wrapper.remove_z_defs(['arg',
-                                                         '-Wl,-z,relro']))
+    self.assertListEqual(
+        ['arg', '-Wl,-z,relro'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z,relro']))
 
-    self.assertListEqual(['arg', '-Wl,-soname,lib.so.1,-z,relro'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', '-Wl,-soname,lib.so.1,-z,defs,-z,relro']))
+    self.assertListEqual(
+        ['arg', '-Wl,-soname,lib.so.1,-z,relro'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-soname,lib.so.1,-z,defs,-z,relro']))
 
-    self.assertListEqual(['arg', '-Wl,-z,relro'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', '-Wl,-z,relro,-z,defs']))
+    self.assertListEqual(
+        ['arg', '-Wl,-z,relro'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z,relro,-z,defs']))
 
-    self.assertListEqual(['arg'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', '-Wl,-z', '-Wl,defs']))
-
-    self.assertListEqual(['arg', 'arg2'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', 'arg2', '-Wl,--no-undefined']))
-
-    self.assertListEqual(['arg', 'arg2'],
-                         compiler_wrapper.remove_z_defs(
-                             ['arg', '-Wl,-z', 'arg2', '-Wl,defs']))
+    self.assertListEqual(
+        ['arg'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z', '-Wl,defs']))
 
+    self.assertListEqual(
+        ['arg', 'arg2'],
+        compiler_wrapper.RemoveZDefs(['arg', '-Wl,-z', 'arg2', '-Wl,--no-undefined']))
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/infra/base-images/base-sanitizer-libs-builder/msan_build.py b/infra/base-images/base-sanitizer-libs-builder/msan_build.py
index 7dd0d82233a5..928b1a596e14 100755
--- a/infra/base-images/base-sanitizer-libs-builder/msan_build.py
+++ b/infra/base-images/base-sanitizer-libs-builder/msan_build.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 ################################################################################
-"""Script to build libraries with MemorySanitizer instrumentation."""
+
 from __future__ import print_function
 import argparse
 import imp
@@ -43,30 +43,12 @@
     '-fno-omit-frame-pointer',
 ]
 
-C_OR_CXX_DEPS = [
-    'libc++1',
-    'libc6',
-    'libc++abi1',
-    'libgcc1',
-    'libstdc++6',
-]
-
-BLACKLISTED_PACKAGES = [
-    'libcapnp-0.5.3',  # fails to compile on newer clang.
-    'libllvm5.0',
-    'libmircore1',
-    'libmircommon7',
-    'libmirclient9',
-    'libmirprotobuf3',
-    'multiarch-support',
-]
-
 
 class MSanBuildException(Exception):
   """Base exception."""
 
 
-def get_track_origins_flag():
+def GetTrackOriginsFlag():
   """Get the track origins flag."""
   if os.getenv('MSAN_NO_TRACK_ORIGINS'):
     return TRACK_ORIGINS_ARG + '0'
@@ -74,12 +56,11 @@ def get_track_origins_flag():
   return TRACK_ORIGINS_ARG + '2'
 
 
-def get_injected_flags():
-  """Get the additional command line arguments."""
-  return INJECTED_ARGS + [get_track_origins_flag()]
+def GetInjectedFlags():
+  return INJECTED_ARGS + [GetTrackOriginsFlag()]
 
 
-def set_up_environment(work_dir):
+def SetUpEnvironment(work_dir):
   """Set up build environment."""
   env = {}
   env['REAL_CLANG_PATH'] = subprocess.check_output(['which', 'clang']).strip()
@@ -90,11 +71,9 @@ def set_up_environment(work_dir):
   bin_dir = os.path.join(work_dir, 'bin')
   os.mkdir(bin_dir)
 
-  dpkg_host_architecture = wrapper_utils.dpkg_host_architecture()
-  wrapper_utils.create_symlinks(
-      compiler_wrapper_path,
-      bin_dir,
-      [
+  dpkg_host_architecture = wrapper_utils.DpkgHostArchitecture()
+  wrapper_utils.CreateSymlinks(
+      compiler_wrapper_path, bin_dir, [
           'clang',
           'clang++',
           # Not all build rules respect $CC/$CXX, so make additional symlinks.
@@ -109,49 +88,54 @@ def set_up_environment(work_dir):
   env['CC'] = os.path.join(bin_dir, 'clang')
   env['CXX'] = os.path.join(bin_dir, 'clang++')
 
-  msan_options = ' '.join(get_injected_flags())
+  MSAN_OPTIONS = ' '.join(GetInjectedFlags())
 
   # We don't use nostrip because some build rules incorrectly break when it is
   # passed. Instead we install our own no-op strip binaries.
   env['DEB_BUILD_OPTIONS'] = ('nocheck parallel=%d' %
                               multiprocessing.cpu_count())
-  env['DEB_CFLAGS_APPEND'] = msan_options
-  env['DEB_CXXFLAGS_APPEND'] = msan_options + ' -stdlib=libc++'
-  env['DEB_CPPFLAGS_APPEND'] = msan_options
-  env['DEB_LDFLAGS_APPEND'] = msan_options
+  env['DEB_CFLAGS_APPEND'] = MSAN_OPTIONS
+  env['DEB_CXXFLAGS_APPEND'] = MSAN_OPTIONS + ' -stdlib=libc++'
+  env['DEB_CPPFLAGS_APPEND'] = MSAN_OPTIONS
+  env['DEB_LDFLAGS_APPEND'] = MSAN_OPTIONS
   env['DPKG_GENSYMBOLS_CHECK_LEVEL'] = '0'
 
   # debian/rules can set DPKG_GENSYMBOLS_CHECK_LEVEL explicitly, so override it.
-  gen_symbols_wrapper = ('#!/bin/sh\n'
-                         'export DPKG_GENSYMBOLS_CHECK_LEVEL=0\n'
-                         '/usr/bin/dpkg-gensymbols "$@"\n')
+  gen_symbols_wrapper = (
+        '#!/bin/sh\n'
+        'export DPKG_GENSYMBOLS_CHECK_LEVEL=0\n'
+        '/usr/bin/dpkg-gensymbols "$@"\n')
 
-  wrapper_utils.install_wrapper(bin_dir, 'dpkg-gensymbols', gen_symbols_wrapper)
+  wrapper_utils.InstallWrapper(bin_dir, 'dpkg-gensymbols',
+                               gen_symbols_wrapper)
 
   # Install no-op strip binaries.
-  no_op_strip = ('#!/bin/sh\n' \
+  no_op_strip = ('#!/bin/sh\n'
                  'exit 0\n')
-  wrapper_utils.install_wrapper(bin_dir, 'strip', no_op_strip,
-                                [dpkg_host_architecture + '-strip'])
+  wrapper_utils.InstallWrapper(
+      bin_dir, 'strip', no_op_strip,
+      [dpkg_host_architecture + '-strip'])
 
   env['PATH'] = bin_dir + ':' + os.environ['PATH']
 
   # nocheck doesn't disable override_dh_auto_test. So we have this hack to try
   # to disable "make check" or "make test" invocations.
-  make_wrapper = ('#!/bin/bash\n'
-                  'if [ "$1" = "test" ] || [ "$1" = "check" ]; then\n'
-                  '  exit 0\n'
-                  'fi\n'
-                  '/usr/bin/make "$@"\n')
-  wrapper_utils.install_wrapper(bin_dir, 'make', make_wrapper)
+  make_wrapper = (
+      '#!/bin/bash\n'
+      'if [ "$1" = "test" ] || [ "$1" = "check" ]; then\n'
+      '  exit 0\n'
+      'fi\n'
+      '/usr/bin/make "$@"\n')
+  wrapper_utils.InstallWrapper(bin_dir, 'make',
+                               make_wrapper)
 
   # Prevent entire build from failing because of bugs/uninstrumented in tools
   # that are part of the build.
   msan_log_dir = os.path.join(work_dir, 'msan')
   os.mkdir(msan_log_dir)
   msan_log_path = os.path.join(msan_log_dir, 'log')
-  env['MSAN_OPTIONS'] = ('halt_on_error=0:exitcode=0:report_umrs=0:log_path=' +
-                         msan_log_path)
+  env['MSAN_OPTIONS'] = (
+      'halt_on_error=0:exitcode=0:report_umrs=0:log_path=' + msan_log_path)
 
   # Increase maximum stack size to prevent tests from failing.
   limit = 128 * 1024 * 1024
@@ -159,7 +143,7 @@ def set_up_environment(work_dir):
   return env
 
 
-def find_package_debs(package_name, work_directory):
+def FindPackageDebs(package_name, work_directory):
   """Find package debs."""
   deb_paths = []
   cache = apt.Cache()
@@ -192,7 +176,7 @@ def find_package_debs(package_name, work_directory):
   return deb_paths
 
 
-def extract_libraries(deb_paths, work_directory, output_directory):
+def ExtractLibraries(deb_paths, work_directory, output_directory):
   """Extract libraries from .deb packages."""
   extract_directory = os.path.join(work_directory, 'extracted')
   if os.path.exists(extract_directory):
@@ -203,6 +187,7 @@ def extract_libraries(deb_paths, work_directory, output_directory):
   for deb_path in deb_paths:
     subprocess.check_call(['dpkg-deb', '-x', deb_path, extract_directory])
 
+  extracted = []
   for root, _, filenames in os.walk(extract_directory):
     if 'libx32' in root or 'lib32' in root:
       continue
@@ -221,8 +206,8 @@ def extract_libraries(deb_paths, work_directory, output_directory):
         os.makedirs(target_dir)
 
       target_file_path = os.path.join(output_directory, rel_file_path)
-      yield target_file_path
-
+      extracted.append(target_file_path)
+        
       if os.path.lexists(target_file_path):
         os.remove(target_file_path)
 
@@ -230,16 +215,17 @@ def extract_libraries(deb_paths, work_directory, output_directory):
         link_path = os.readlink(file_path)
         if os.path.isabs(link_path):
           # Make absolute links relative.
-          link_path = os.path.relpath(link_path,
-                                      os.path.join('/', rel_directory))
+          link_path = os.path.relpath(
+              link_path, os.path.join('/', rel_directory))
 
         os.symlink(link_path, target_file_path)
       else:
         shutil.copy2(file_path, target_file_path)
 
+  return extracted
+
 
-def get_package(package_name):
-  """Factory for Package objects."""
+def GetPackage(package_name):
   apt_cache = apt.Cache()
   version = apt_cache[package_name].candidate
   source_name = version.source_name
@@ -255,11 +241,11 @@ def get_package(package_name):
   return module.Package(version)
 
 
-def patch_rpath(path, output_directory):
+def PatchRpath(path, output_directory):
   """Patch rpath to be relative to $ORIGIN."""
   try:
-    rpaths = subprocess.check_output(['patchelf', '--print-rpath',
-                                      path]).strip()
+    rpaths = subprocess.check_output(
+        ['patchelf', '--print-rpath', path]).strip()
   except subprocess.CalledProcessError:
     return
 
@@ -276,17 +262,37 @@ def patch_rpath(path, output_directory):
       processed_rpath.append(rpath)
       continue
 
-    processed_rpath.append(
-        os.path.join('$ORIGIN', os.path.relpath(rpath, rel_directory)))
+    processed_rpath.append(os.path.join(
+        '$ORIGIN',
+        os.path.relpath(rpath, rel_directory)))
 
   processed_rpath = ':'.join(processed_rpath)
   print('Patching rpath for', path, 'to', processed_rpath)
   subprocess.check_call(
-      ['patchelf', '--force-rpath', '--set-rpath', processed_rpath, path])
+      ['patchelf', '--force-rpath', '--set-rpath',
+       processed_rpath, path])
 
 
-def _collect_dependencies(apt_cache, pkg, cache, dependencies):
+def _CollectDependencies(apt_cache, pkg, cache, dependencies):
   """Collect dependencies that need to be built."""
+  C_OR_CXX_DEPS = [
+      'libc++1',
+      'libc6',
+      'libc++abi1',
+      'libgcc1',
+      'libstdc++6',
+  ]
+
+  BLACKLISTED_PACKAGES = [
+      'libcapnp-0.5.3',  # fails to compile on newer clang.
+      'libllvm5.0',
+      'libmircore1',
+      'libmircommon7',
+      'libmirclient9',
+      'libmirprotobuf3',
+      'multiarch-support',
+  ]
+
   if pkg.name in BLACKLISTED_PACKAGES:
     return False
 
@@ -303,9 +309,8 @@ def _collect_dependencies(apt_cache, pkg, cache, dependencies):
     if dependency.name in cache:
       is_c_or_cxx |= cache[dependency.name]
     else:
-      is_c_or_cxx |= _collect_dependencies(apt_cache,
-                                           apt_cache[dependency.name], cache,
-                                           dependencies)
+      is_c_or_cxx |= _CollectDependencies(apt_cache, apt_cache[dependency.name],
+                                          cache, dependencies)
   if is_c_or_cxx:
     dependencies.append(pkg.name)
 
@@ -313,24 +318,20 @@ def _collect_dependencies(apt_cache, pkg, cache, dependencies):
   return is_c_or_cxx
 
 
-def get_build_list(package_name):
+def GetBuildList(package_name):
   """Get list of packages that need to be built including dependencies."""
   apt_cache = apt.Cache()
   pkg = apt_cache[package_name]
 
   dependencies = []
-  _collect_dependencies(apt_cache, pkg, {}, dependencies)
+  _CollectDependencies(apt_cache, pkg, {}, dependencies)
   return dependencies
 
 
-class MSanBuilder:
+class MSanBuilder(object):
   """MSan builder."""
 
-  def __init__(self,
-               debug=False,
-               log_path=None,
-               work_dir=None,
-               no_track_origins=False):
+  def __init__(self, debug=False, log_path=None, work_dir=None, no_track_origins=False):
     self.debug = debug
     self.log_path = log_path
     self.work_dir = work_dir
@@ -345,7 +346,7 @@ def __enter__(self):
       shutil.rmtree(self.work_dir, ignore_errors=True)
 
     os.makedirs(self.work_dir)
-    self.env = set_up_environment(self.work_dir)
+    self.env = SetUpEnvironment(self.work_dir)
 
     if self.debug and self.log_path:
       self.env['WRAPPER_DEBUG_LOG_PATH'] = self.log_path
@@ -359,16 +360,16 @@ def __exit__(self, exc_type, exc_value, traceback):
     if not self.debug:
       shutil.rmtree(self.work_dir, ignore_errors=True)
 
-  def build(self, package_name, output_directory, create_subdirs=False):
+  def Build(self, package_name, output_directory, create_subdirs=False):
     """Build the package and write results into the output directory."""
-    deb_paths = find_package_debs(package_name, self.work_dir)
+    deb_paths = FindPackageDebs(package_name, self.work_dir)
     if deb_paths:
       print('Source package already built for', package_name)
     else:
-      pkg = get_package(package_name)
+      pkg = GetPackage(package_name)
 
-      pkg.install_build_deps()
-      source_directory = pkg.download_source(self.work_dir)
+      pkg.InstallBuildDeps()
+      source_directory = pkg.DownloadSource(self.work_dir)
       print('Source downloaded to', source_directory)
 
       # custom bin directory for custom build scripts to write wrappers.
@@ -377,10 +378,10 @@ def build(self, package_name, output_directory, create_subdirs=False):
       env = self.env.copy()
       env['PATH'] = custom_bin_dir + ':' + env['PATH']
 
-      pkg.build(source_directory, env, custom_bin_dir)
+      pkg.Build(source_directory, env, custom_bin_dir)
       shutil.rmtree(custom_bin_dir, ignore_errors=True)
 
-      deb_paths = find_package_debs(package_name, self.work_dir)
+      deb_paths = FindPackageDebs(package_name, self.work_dir)
 
     if not deb_paths:
       raise MSanBuildException('Failed to find .deb packages.')
@@ -392,25 +393,22 @@ def build(self, package_name, output_directory, create_subdirs=False):
     else:
       extract_directory = output_directory
 
-    extracted_paths = list(
-        extract_libraries(deb_paths, self.work_dir, extract_directory))
+    extracted_paths = ExtractLibraries(deb_paths, self.work_dir,
+                                       extract_directory)
     for extracted_path in extracted_paths:
       if not os.path.islink(extracted_path):
-        patch_rpath(extracted_path, extract_directory)
+        PatchRpath(extracted_path, extract_directory)
 
 
 def main():
-  """Builds packages with MemorySanitizer instrumentation."""
   parser = argparse.ArgumentParser('msan_build.py', description='MSan builder.')
   parser.add_argument('package_names', nargs='+', help='Name of the packages.')
   parser.add_argument('output_dir', help='Output directory.')
-  parser.add_argument('--create-subdirs',
-                      action='store_true',
+  parser.add_argument('--create-subdirs', action='store_true',
                       help=('Create subdirectories in the output '
                             'directory for each package.'))
   parser.add_argument('--work-dir', help='Work directory.')
-  parser.add_argument('--no-build-deps',
-                      action='store_true',
+  parser.add_argument('--no-build-deps', action='store_true',
                       help='Don\'t build dependencies.')
   parser.add_argument('--debug', action='store_true', help='Enable debug mode.')
   parser.add_argument('--log-path', help='Log path for debugging.')
@@ -433,7 +431,7 @@ def main():
 
     # Get list of packages to build, including all dependencies.
     for package_name in args.package_names:
-      for dep in get_build_list(package_name):
+      for dep in GetBuildList(package_name):
         if dep in all_packages:
           continue
 
@@ -447,12 +445,11 @@ def main():
   for package_name in package_names:
     print('\t', package_name)
 
-  with MSanBuilder(debug=args.debug,
-                   log_path=args.log_path,
+  with MSanBuilder(debug=args.debug, log_path=args.log_path,
                    work_dir=args.work_dir,
                    no_track_origins=args.no_track_origins) as builder:
     for package_name in package_names:
-      builder.build(package_name, args.output_dir, args.create_subdirs)
+      builder.Build(package_name, args.output_dir, args.create_subdirs)
 
 
 if __name__ == '__main__':
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/boost1_58.py b/infra/base-images/base-sanitizer-libs-builder/packages/boost1_58.py
index 20d1b9df1645..8071b7ecd4f7 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/boost1_58.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/boost1_58.py
@@ -14,17 +14,16 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for boost1.58."""
+
 import package
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """boost1.58 package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('boost1.58', apt_version)
 
-  def pre_build(self, _source_directory, env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for boost1.58."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     # Otherwise py_nonblocking.cpp fails to build.
     env['DEB_CXXFLAGS_APPEND'] += ' -std=c++98'
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/gnutls28.py b/infra/base-images/base-sanitizer-libs-builder/packages/gnutls28.py
index efe8d34b1c66..f8407a66876b 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/gnutls28.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/gnutls28.py
@@ -14,22 +14,24 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for gnutls28."""
+
+import os
+import shutil
+
 import package
 import wrapper_utils
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """gnutls28 package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('gnutls28', apt_version)
 
-  def pre_build(self, _source_directory, _env, custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for gnutls28."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     configure_wrapper = (
         '#!/bin/bash\n'
         '/usr/bin/dh_auto_configure "$@" --disable-hardware-acceleration')
 
-    wrapper_utils.install_wrapper(custom_bin_dir, 'dh_auto_configure',
-                                  configure_wrapper)
+    wrapper_utils.InstallWrapper(
+        custom_bin_dir, 'dh_auto_configure', configure_wrapper)
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/libgcrypt20.py b/infra/base-images/base-sanitizer-libs-builder/packages/libgcrypt20.py
index 948240ae37f0..9d200af6f62b 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/libgcrypt20.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/libgcrypt20.py
@@ -14,21 +14,24 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for libgcrypt20."""
+
+import os
+import shutil
+
 import package
 import wrapper_utils
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """libgcrypt20 package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('libgcrypt20', apt_version)
 
-  def pre_build(self, _source_directory, _env, custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for libgcrypt20."""
-    configure_wrapper = ('#!/bin/bash\n'
-                         '/usr/bin/dh_auto_configure "$@" --disable-asm')
+  def PreBuild(self, source_directory, env, custom_bin_dir):
+    configure_wrapper = (
+        '#!/bin/bash\n'
+        '/usr/bin/dh_auto_configure "$@" --disable-asm')
 
-    wrapper_utils.install_wrapper(custom_bin_dir, 'dh_auto_configure',
-                                  configure_wrapper)
+    wrapper_utils.InstallWrapper(
+        custom_bin_dir, 'dh_auto_configure', configure_wrapper)
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/mesa.py b/infra/base-images/base-sanitizer-libs-builder/packages/mesa.py
index 9b3d6e3a18da..ec2e9d217ef4 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/mesa.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/mesa.py
@@ -14,16 +14,15 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for mesa."""
+
 import package
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """mesa package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('mesa', apt_version)
 
-  def pre_build(self, _source_directory, env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for mesa."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     env['DEB_CXXFLAGS_APPEND'] += ' -std=c++11'
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/nettle.py b/infra/base-images/base-sanitizer-libs-builder/packages/nettle.py
index 26756579be56..e1b0e2f81346 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/nettle.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/nettle.py
@@ -14,28 +14,28 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom configure options for nettle."""
+
 import os
 import shutil
 
 import package
 
 
-def add_no_asm_arg(config_path):
+def AddNoAsmArg(config_path):
   """Add --disable-assembler to config scripts."""
   shutil.move(config_path, config_path + '.real')
-  with open(config_path, 'w') as config_file:
-    config_file.write('#!/bin/sh\n'
-                      '%s.real --disable-assembler "$@"\n' % config_path)
-  os.chmod(config_path, 0o755)
+  with open(config_path, 'w') as f:
+    f.write(
+        '#!/bin/sh\n'
+        '%s.real --disable-assembler "$@"\n' % config_path)
+  os.chmod(config_path, 0755)
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """nettle package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('nettle', apt_version)
 
-  def pre_build(self, source_directory, _env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Hook function to customize nettle's configuration before building."""
-    add_no_asm_arg(os.path.join(source_directory, 'configure'))
+  def PreBuild(self, source_directory, env, custom_bin_dir):
+    AddNoAsmArg(os.path.join(source_directory, 'configure'))
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/openssl.py b/infra/base-images/base-sanitizer-libs-builder/packages/openssl.py
index 0fb311ff84c0..e24ccc58813d 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/openssl.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/openssl.py
@@ -14,29 +14,29 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom configure options for openssl."""
+
 import os
 import shutil
 
 import package
 
 
-def add_no_asm_arg(config_path):
+def AddNoAsmArg(config_path):
   """Add --no-asm to config scripts."""
   shutil.move(config_path, config_path + '.real')
-  with open(config_path, 'w') as config_file:
-    config_file.write('#!/bin/sh\n' \
-                      '%s.real no-asm "$@"\n' % config_path)
-  os.chmod(config_path, 0o755)
+  with open(config_path, 'w') as f:
+    f.write(
+        '#!/bin/sh\n'
+        '%s.real no-asm "$@"\n' % config_path)
+  os.chmod(config_path, 0755)
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """openssl package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('openssl', apt_version)
 
-  def pre_build(self, source_directory, _env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Hook function to customize openssl's configuration before building."""
-    add_no_asm_arg(os.path.join(source_directory, 'Configure'))
-    add_no_asm_arg(os.path.join(source_directory, 'config'))
+  def PreBuild(self, source_directory, env, custom_bin_dir):
+    AddNoAsmArg(os.path.join(source_directory, 'Configure'))
+    AddNoAsmArg(os.path.join(source_directory, 'config'))
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/package.py b/infra/base-images/base-sanitizer-libs-builder/packages/package.py
index a8d40e17bc9a..059c23587051 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/package.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/package.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 ################################################################################
-"""Base class and utility functions for all libraries that require customized build processes."""
+
 import os
 import subprocess
 
@@ -23,62 +23,60 @@
 SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
 
 
-def apply_patch(source_directory, patch_name):
+def ApplyPatch(source_directory, patch_name):
   """Apply custom patch."""
-  subprocess.check_call(
-      ['patch', '-p1', '-i',
-       os.path.join(SCRIPT_DIR, patch_name)],
-      cwd=source_directory)
+  subprocess.check_call(['patch', '-p1', '-i',
+                         os.path.join(SCRIPT_DIR, patch_name)],
+                        cwd=source_directory)
 
 
 class PackageException(Exception):
   """Base package exception."""
 
 
-class Package:
+class Package(object):
   """Base package."""
 
   def __init__(self, name, apt_version):
     self.name = name
     self.apt_version = apt_version
 
-  def pre_build(self, _source_directory, _env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Default no-op pre-build hook function."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     return
 
-  def post_build(self, _source_directory, _env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Default no-op post-build hook function."""
+  def PostBuild(self, source_directory, env, custom_bin_dir):
     return
 
-  def pre_download(self, _download_directory):  # pylint: disable=no-self-use
-    """Default no-op pre-download hook function."""
+  def PreDownload(self, download_directory):
     return
 
-  def post_download(self, _source_directory):  # pylint: disable=no-self-use
-    """Default no-op post-download hook function."""
+  def PostDownload(self, source_directory):
     return
 
-  def install_build_deps(self):
+  def InstallBuildDeps(self):
     """Install build dependencies for a package."""
     subprocess.check_call(['apt-get', 'update'])
     subprocess.check_call(['apt-get', 'build-dep', '-y', self.name])
 
     # Reload package after update.
-    self.apt_version = apt.Cache()[self.apt_version.package.name].candidate
+    self.apt_version = (
+        apt.Cache()[self.apt_version.package.name].candidate)
 
-  def download_source(self, download_directory):
+  def DownloadSource(self, download_directory):
     """Download the source for a package."""
-    self.pre_download(download_directory)
+    self.PreDownload(download_directory)
 
     source_directory = self.apt_version.fetch_source(download_directory)
 
-    self.post_download(source_directory)
+    self.PostDownload(source_directory)
     return source_directory
 
-  def build(self, source_directory, env, custom_bin_dir):
+  def Build(self, source_directory, env, custom_bin_dir):
     """Build .deb packages."""
-    self.pre_build(source_directory, env, custom_bin_dir)
-    subprocess.check_call(['dpkg-buildpackage', '-us', '-uc', '-B'],
-                          cwd=source_directory,
-                          env=env)
-    self.post_build(source_directory, env, custom_bin_dir)
+    self.PreBuild(source_directory, env, custom_bin_dir)
+    subprocess.check_call(
+        ['dpkg-buildpackage', '-us', '-uc', '-B'],
+        cwd=source_directory, env=env)
+    self.PostBuild(source_directory, env, custom_bin_dir)
+
+
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/pixman.py b/infra/base-images/base-sanitizer-libs-builder/packages/pixman.py
index e693298ed590..d63b1468f7b0 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/pixman.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/pixman.py
@@ -14,8 +14,9 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for pixman."""
+
 import os
+import shutil
 
 import package
 
@@ -26,15 +27,16 @@ class Package(package.Package):
   def __init__(self, apt_version):
     super(Package, self).__init__('pixman', apt_version)
 
-  def post_download(self, source_directory):  # pylint: disable=no-self-use
-    """Workaround for incorrect checking of GCC vector extension availability."""
-    os.system('sed s/support_for_gcc_vector_extensions=yes/'
-              'support_for_gcc_vector_extensions=no/ -i %s/configure.ac' %
-              source_directory)
+  def PostDownload(self, source_directory):
+    # Incorrect checking of GCC vector extension availability.
+    os.system(
+      'sed s/support_for_gcc_vector_extensions=yes/'
+      'support_for_gcc_vector_extensions=no/ -i %s/configure.ac' %
+      source_directory)
 
-  def pre_build(self, _source_directory, env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for pixman."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     blacklist_flag = ' -fsanitize-blacklist=' + os.path.join(
-        os.path.dirname(os.path.abspath(__file__)), 'pixman_blacklist.txt')
+        os.path.dirname(os.path.abspath(__file__)),
+        'pixman_blacklist.txt')
     env['DEB_CXXFLAGS_APPEND'] += blacklist_flag
     env['DEB_CFLAGS_APPEND'] += blacklist_flag
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/pulseaudio.py b/infra/base-images/base-sanitizer-libs-builder/packages/pulseaudio.py
index c4fd9f4a6b26..853b9e7240bf 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/pulseaudio.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/pulseaudio.py
@@ -14,20 +14,22 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for PulseAudio."""
+
 from __future__ import print_function
+import glob
 import os
+import subprocess
 
 import package
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """PulseAudio package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('pulseaudio', apt_version)
 
-  def post_download(self, source_directory):  # pylint: disable=no-self-use
+  def PostDownload(self, source_directory):
     """Remove blacklisted patches."""
     # Fix *droid* patches.
     bad_patch_path = os.path.join(
@@ -37,4 +39,4 @@ def post_download(self, source_directory):  # pylint: disable=no-self-use
       return
 
     print('Applying custom patches.')
-    package.apply_patch(source_directory, 'pulseaudio_fix_android.patch')
+    package.ApplyPatch(source_directory, 'pulseaudio_fix_android.patch')
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/sqlite3.py b/infra/base-images/base-sanitizer-libs-builder/packages/sqlite3.py
index caed9c4d11f5..3e1a1070fa69 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/sqlite3.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/sqlite3.py
@@ -14,19 +14,19 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for sqlite3."""
+
 import os
 
 import package
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """sqlite3 package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('sqlite3', apt_version)
 
-  def pre_build(self, source_directory, _env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for sqlite3."""
-    os.system('sed -i "s/package ifneeded sqlite3//" %s/debian/rules' %
-              source_directory)
+  def PreBuild(self, source_directory, env, custom_bin_dir):
+    os.system(
+        'sed -i "s/package ifneeded sqlite3//" %s/debian/rules' %
+        source_directory)
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/systemd.py b/infra/base-images/base-sanitizer-libs-builder/packages/systemd.py
index 48922d8badda..5cb6d60bedc5 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/systemd.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/systemd.py
@@ -14,27 +14,29 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for systemd."""
+
 from __future__ import print_function
+import glob
+import os
+import subprocess
 
 import package
 import wrapper_utils
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """systemd package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('systemd', apt_version)
 
-  def pre_build(self, _source_directory, _env, custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build installation of a wrapper script for systemd."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     # Hide msan symbols from nm. the systemd build system uses this to find
     # undefined symbols and errors out if it does.
-    nm_wrapper = ('#!/bin/bash\n'
-                  '/usr/bin/nm "$@" | grep -E -v "U (__msan|memset)"\n'
-                  'exit ${PIPESTATUS[0]}\n')
+    nm_wrapper = (
+        '#!/bin/bash\n'
+        '/usr/bin/nm "$@" | grep -E -v "U (__msan|memset)"\n'
+        'exit ${PIPESTATUS[0]}\n')
 
-    wrapper_utils.install_wrapper(
-        custom_bin_dir, 'nm', nm_wrapper,
-        [wrapper_utils.dpkg_host_architecture() + '-nm'])
+    wrapper_utils.InstallWrapper(custom_bin_dir, 'nm', nm_wrapper,
+                                 [wrapper_utils.DpkgHostArchitecture() + '-nm'])
diff --git a/infra/base-images/base-sanitizer-libs-builder/packages/tar.py b/infra/base-images/base-sanitizer-libs-builder/packages/tar.py
index 6aab2825eb23..74abd5c72030 100644
--- a/infra/base-images/base-sanitizer-libs-builder/packages/tar.py
+++ b/infra/base-images/base-sanitizer-libs-builder/packages/tar.py
@@ -14,16 +14,15 @@
 # limitations under the License.
 #
 ################################################################################
-"""Custom options for tar."""
+
 import package
 
 
-class Package(package.Package):  # pylint: disable=too-few-public-methods
+class Package(package.Package):
   """tar package."""
 
   def __init__(self, apt_version):
     super(Package, self).__init__('tar', apt_version)
 
-  def pre_build(self, _source_directory, env, _custom_bin_dir):  # pylint: disable=no-self-use
-    """Pre-build configuration for tar."""
+  def PreBuild(self, source_directory, env, custom_bin_dir):
     env['FORCE_UNSAFE_CONFIGURE'] = '1'
diff --git a/infra/base-images/base-sanitizer-libs-builder/patch_build.py b/infra/base-images/base-sanitizer-libs-builder/patch_build.py
index e594ce0c121d..cb1f4b1d74a2 100755
--- a/infra/base-images/base-sanitizer-libs-builder/patch_build.py
+++ b/infra/base-images/base-sanitizer-libs-builder/patch_build.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 #
 ################################################################################
-"""Helper script to patch rpath in all binaries to point to instrumented libraries."""
+
 from __future__ import print_function
 import argparse
 import os
@@ -25,36 +25,27 @@
 
 INSTRUMENTED_LIBRARIES_DIRNAME = 'instrumented_libraries'
 MSAN_LIBS_PATH = os.getenv('MSAN_LIBS_PATH', '/msan')
-INTERCEPTED_LIBRARIES = {
-    '/lib/x86_64-linux-gnu/libm.so.6',
-    '/lib/x86_64-linux-gnu/libpthread.so.0',
-    '/lib/x86_64-linux-gnu/librt.so.1',
-    '/lib/x86_64-linux-gnu/libdl.so.2',
-    '/lib/x86_64-linux-gnu/libgcc_s.so.1',
-    '/lib/x86_64-linux-gnu/libc.so.6',
-}
-LDD_OUTPUT_PATTERN = re.compile(r'\s*([^\s]+)\s*=>\s*([^\s]+)')
-
-
-def is_elf(file_path):
+
+
+def IsElf(file_path):
   """Whether if the file is an elf file."""
-  with open(file_path) as elf_file:
-    return elf_file.read(4) == '\x7fELF'
+  with open(file_path) as f:
+    return f.read(4) == '\x7fELF'
 
 
-def ldd(binary_path):
+def Ldd(binary_path):
   """Run ldd on a file."""
   try:
-    output = subprocess.check_output(['ldd', binary_path],
-                                     stderr=subprocess.STDOUT)
+    output = subprocess.check_output(['ldd', binary_path], stderr=subprocess.STDOUT)
   except subprocess.CalledProcessError:
     print('Failed to call ldd on', binary_path, file=sys.stderr)
     return []
 
   libs = []
 
+  OUTPUT_PATTERN = re.compile(r'\s*([^\s]+)\s*=>\s*([^\s]+)')
   for line in output.splitlines():
-    match = LDD_OUTPUT_PATTERN.match(line)
+    match = OUTPUT_PATTERN.match(line)
     if not match:
       continue
 
@@ -63,12 +54,12 @@ def ldd(binary_path):
   return libs
 
 
-def find_lib(path):
+def FindLib(path):
   """Find instrumented version of lib."""
   candidate_path = os.path.join(MSAN_LIBS_PATH, path[1:])
   if os.path.exists(candidate_path):
     return candidate_path
-
+  
   for lib_dir in os.listdir(MSAN_LIBS_PATH):
     candidate_path = os.path.join(MSAN_LIBS_PATH, lib_dir, path[1:])
     if os.path.exists(candidate_path):
@@ -77,20 +68,18 @@ def find_lib(path):
   return None
 
 
-def patch_binary(binary_path, instrumented_dir):
+def PatchBinary(binary_path, instrumented_dir):
   """Patch binary to link to instrumented libs."""
   extra_rpaths = set()
 
-  for _name, path in ldd(binary_path):
+  for name, path in Ldd(binary_path):
     if not os.path.isabs(path):
       continue
 
-    instrumented_path = find_lib(path)
+    instrumented_path = FindLib(path)
     if not instrumented_path:
-      if path not in INTERCEPTED_LIBRARIES:
-        print('WARNING: Instrumented library not found for',
-              path,
-              file=sys.stderr)
+      print('WARNING: Instrumented library not found for', path,
+            file=sys.stderr)
       continue
 
     target_path = os.path.join(instrumented_dir, path[1:])
@@ -116,12 +105,12 @@ def patch_binary(binary_path, instrumented_dir):
   print('Patching rpath for', binary_path, 'from', existing_rpaths, 'to',
         processed_rpaths)
 
-  subprocess.check_call([
-      'patchelf', '--force-rpath', '--set-rpath', processed_rpaths, binary_path
-  ])
+  subprocess.check_call(
+      ['patchelf', '--force-rpath', '--set-rpath',
+       processed_rpaths, binary_path])
 
 
-def patch_build(output_directory):
+def PatchBuild(output_directory):
   """Patch build to use msan libs."""
   instrumented_dir = os.path.join(output_directory,
                                   INSTRUMENTED_LIBRARIES_DIRNAME)
@@ -135,21 +124,19 @@ def patch_build(output_directory):
       if os.path.islink(file_path):
         continue
 
-      if not is_elf(file_path):
+      if not IsElf(file_path):
         continue
 
-      patch_binary(file_path, instrumented_dir)
+      PatchBinary(file_path, instrumented_dir)
 
 
 def main():
-  """Patch binaries to use instrumented libraries for all their dynamic objects."""
-  parser = argparse.ArgumentParser('patch_build.py',
-                                   description='MSan build patcher.')
+  parser = argparse.ArgumentParser('patch_build.py', description='MSan build patcher.')
   parser.add_argument('output_dir', help='Output directory.')
 
   args = parser.parse_args()
 
-  patch_build(os.path.abspath(args.output_dir))
+  PatchBuild(os.path.abspath(args.output_dir))
 
 
 if __name__ == '__main__':
diff --git a/infra/base-images/base-sanitizer-libs-builder/wrapper_utils.py b/infra/base-images/base-sanitizer-libs-builder/wrapper_utils.py
index 8d790bc76b99..0cbf1677d082 100644
--- a/infra/base-images/base-sanitizer-libs-builder/wrapper_utils.py
+++ b/infra/base-images/base-sanitizer-libs-builder/wrapper_utils.py
@@ -14,32 +14,33 @@
 # limitations under the License.
 #
 ################################################################################
-"""Functions to help with wrapper scripts."""
+
 from __future__ import print_function
 
+import contextlib
 import os
 import subprocess
 
 
-def dpkg_host_architecture():
+def DpkgHostArchitecture():
   """Return the host architecture."""
-  return subprocess.check_output(['dpkg-architecture',
-                                  '-qDEB_HOST_GNU_TYPE']).strip()
+  return subprocess.check_output(
+      ['dpkg-architecture', '-qDEB_HOST_GNU_TYPE']).strip()
 
 
-def install_wrapper(bin_dir, name, contents, extra_names=None):
+def InstallWrapper(bin_dir, name, contents, extra_names=None):
   """Install a custom wrapper script into |bin_dir|."""
   path = os.path.join(bin_dir, name)
-  with open(path, 'w') as wrapper_file:
-    wrapper_file.write(contents)
+  with open(path, 'w') as f:
+    f.write(contents)
 
-  os.chmod(path, 0o755)
+  os.chmod(path, 0755)
 
   if extra_names:
-    create_symlinks(path, bin_dir, extra_names)
+    CreateSymlinks(path, bin_dir, extra_names)
 
 
-def create_symlinks(original_path, bin_dir, extra_names):
+def CreateSymlinks(original_path, bin_dir, extra_names):
   """Create symlinks."""
   for extra_name in extra_names:
     extra_path = os.path.join(bin_dir, extra_name)