diff --git a/metaflow/extension_support.py b/metaflow/extension_support.py
index b6d04935570..d6040b328e9 100644
--- a/metaflow/extension_support.py
+++ b/metaflow/extension_support.py
@@ -1,3 +1,5 @@
+from __future__ import print_function
+
 import importlib
 import json
 import os
diff --git a/metaflow/plugins/cards/card_datastore.py b/metaflow/plugins/cards/card_datastore.py
index a31c26425ad..5065d4a7523 100644
--- a/metaflow/plugins/cards/card_datastore.py
+++ b/metaflow/plugins/cards/card_datastore.py
@@ -26,7 +26,8 @@
 
 def path_spec_resolver(pathspec):
     splits = pathspec.split("/")
-    return (*splits, *[None] * (4 - len(splits)))
+    splits.extend([None] * (4 - len(splits)))
+    return tuple(splits)
 
 
 def is_file_present(path):
diff --git a/metaflow/plugins/cards/card_modules/__init__.py b/metaflow/plugins/cards/card_modules/__init__.py
index cd1e3105d60..3a1f0fac116 100644
--- a/metaflow/plugins/cards/card_modules/__init__.py
+++ b/metaflow/plugins/cards/card_modules/__init__.py
@@ -97,16 +97,15 @@ def _load_external_cards():
 
 def _get_external_card_package_paths():
     pkg_iter = _get_external_card_packages(with_paths=True)
-    if pkg_iter is None:
-        return None
-    for (
-        mf_extension_parent_path,
-        relative_path_to_module,
-        _,
-    ) in pkg_iter:
-        module_pth = os.path.join(mf_extension_parent_path, relative_path_to_module)
-        arcname = relative_path_to_module
-        yield module_pth, arcname
+    if pkg_iter is not None:
+        for (
+            mf_extension_parent_path,
+            relative_path_to_module,
+            _,
+        ) in pkg_iter:
+            module_pth = os.path.join(mf_extension_parent_path, relative_path_to_module)
+            arcname = relative_path_to_module
+            yield module_pth, arcname
 
 
 MF_EXTERNAL_CARDS = _load_external_cards()
diff --git a/metaflow/plugins/cards/card_modules/renderer_tools.py b/metaflow/plugins/cards/card_modules/renderer_tools.py
index 4f4e33e00e6..b930d1253c9 100644
--- a/metaflow/plugins/cards/card_modules/renderer_tools.py
+++ b/metaflow/plugins/cards/card_modules/renderer_tools.py
@@ -6,7 +6,7 @@
 
 
 def _render_component_safely(
-    component, render_func, *args, return_error_component=True, **kwargs
+    component, render_func, return_error_component, *args, **kwargs
 ):
     rendered_obj = None
     try:
@@ -42,8 +42,6 @@ def render_safely(func):
     """
     # expects a renderer func
     def ret_func(self, *args, **kwargs):
-        return _render_component_safely(
-            self, func, *args, return_error_component=True, **kwargs
-        )
+        return _render_component_safely(self, func, True, *args, **kwargs)
 
     return ret_func
diff --git a/metaflow/plugins/cards/component_serializer.py b/metaflow/plugins/cards/component_serializer.py
index 1d2ec7dd487..c120f229e00 100644
--- a/metaflow/plugins/cards/component_serializer.py
+++ b/metaflow/plugins/cards/component_serializer.py
@@ -35,12 +35,11 @@ class CardComponentCollector:
         - [x] Classes with `ALLOW_USER_COMPONENTS=False` are never default editable.
     - [x] The user can specify an `id` argument to a card, in which case the card is editable through `current.card[id].append`.
         - [x] A card with an id can be also default editable, if there are no other cards that are eligible to be default editable.
-    - [x] If multiple default-editable cards exist but only one card doesn’t have an id, the card without an id is considered to be default editable.
-    - [x] If we can’t resolve a single default editable card through the above rules, `current.card`.append calls show a warning but the call doesn’t fail.
+    - [x] If multiple default-editable cards exist but only one card doesn't have an id, the card without an id is considered to be default editable.
+    - [x] If we can't resolve a single default editable card through the above rules, `current.card`.append calls show a warning but the call doesn't fail.
     - [x] A card that is not default editable can be still edited through:
         - [x] its `current.card['myid']`
-        - [x] by looking it up by its type, e.g. `current.card.get(type=’pytorch’)`.
-
+        - [x] by looking it up by its type, e.g. `current.card.get(type='pytorch')`.
     """
 
     def __init__(self, logger=None):