diff --git a/casbin/__init__.py b/casbin/__init__.py
index b838ce20..0e159ba8 100644
--- a/casbin/__init__.py
+++ b/casbin/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .enforcer import *
 from .synced_enforcer import SyncedEnforcer
 from .distributed_enforcer import DistributedEnforcer
diff --git a/casbin/config/__init__.py b/casbin/config/__init__.py
index cca5d9bd..fd34cf7f 100644
--- a/casbin/config/__init__.py
+++ b/casbin/config/__init__.py
@@ -1 +1,15 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .config import Config
diff --git a/casbin/config/config.py b/casbin/config/config.py
index 9dba5b3e..ced352c0 100644
--- a/casbin/config/config.py
+++ b/casbin/config/config.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from io import StringIO
 
 
diff --git a/casbin/core_enforcer.py b/casbin/core_enforcer.py
index a5e75580..31ba25d5 100644
--- a/casbin/core_enforcer.py
+++ b/casbin/core_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import logging, copy
 
 from casbin.effect import Effector, get_effector, effect_to_bool
diff --git a/casbin/distributed_enforcer.py b/casbin/distributed_enforcer.py
index 6ae14e6e..b01778d3 100644
--- a/casbin/distributed_enforcer.py
+++ b/casbin/distributed_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin import SyncedEnforcer
 import logging
 
diff --git a/casbin/effect/__init__.py b/casbin/effect/__init__.py
index 88bc31da..ede8aa8f 100644
--- a/casbin/effect/__init__.py
+++ b/casbin/effect/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .default_effectors import (
     AllowOverrideEffector,
     DenyOverrideEffector,
diff --git a/casbin/effect/default_effectors.py b/casbin/effect/default_effectors.py
index 9e00ee41..7e5ae578 100644
--- a/casbin/effect/default_effectors.py
+++ b/casbin/effect/default_effectors.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .effector import Effector
 
 
diff --git a/casbin/effect/effector.py b/casbin/effect/effector.py
index 45106db4..71251ded 100644
--- a/casbin/effect/effector.py
+++ b/casbin/effect/effector.py
@@ -1,3 +1,18 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
+
 class Effector:
     """Effector is the interface for Casbin effectors."""
 
diff --git a/casbin/enforcer.py b/casbin/enforcer.py
index f45473fb..636baf0c 100644
--- a/casbin/enforcer.py
+++ b/casbin/enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from functools import partial
 
 from casbin.management_enforcer import ManagementEnforcer
diff --git a/casbin/frontend.py b/casbin/frontend.py
index c13851ec..7ec7d788 100644
--- a/casbin/frontend.py
+++ b/casbin/frontend.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import json
 
 
diff --git a/casbin/internal_enforcer.py b/casbin/internal_enforcer.py
index 87879544..2a15fe0a 100644
--- a/casbin/internal_enforcer.py
+++ b/casbin/internal_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin.core_enforcer import CoreEnforcer
 from casbin.model.policy_op import PolicyOp
 
diff --git a/casbin/management_enforcer.py b/casbin/management_enforcer.py
index 6870cb99..3f1155f9 100644
--- a/casbin/management_enforcer.py
+++ b/casbin/management_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin.internal_enforcer import InternalEnforcer
 from casbin.model.policy_op import PolicyOp
 
diff --git a/casbin/model/__init__.py b/casbin/model/__init__.py
index 2bdda40b..5491ba83 100644
--- a/casbin/model/__init__.py
+++ b/casbin/model/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .assertion import Assertion
 from .model import Model
 from .policy import Policy
diff --git a/casbin/model/assertion.py b/casbin/model/assertion.py
index c2f52c68..174cbe31 100644
--- a/casbin/model/assertion.py
+++ b/casbin/model/assertion.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import logging
 from casbin.model.policy_op import PolicyOp
 
diff --git a/casbin/model/function.py b/casbin/model/function.py
index aedc9ef7..fdd4a227 100644
--- a/casbin/model/function.py
+++ b/casbin/model/function.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin import util
 
 
diff --git a/casbin/model/model.py b/casbin/model/model.py
index fd4e775d..c0b8d9c5 100644
--- a/casbin/model/model.py
+++ b/casbin/model/model.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from . import Assertion
 from casbin import util, config
 from .policy import Policy
diff --git a/casbin/model/policy.py b/casbin/model/policy.py
index 175dbf3b..7c77cc74 100644
--- a/casbin/model/policy.py
+++ b/casbin/model/policy.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import logging
 
 DEFAULT_SEP = ","
diff --git a/casbin/model/policy_op.py b/casbin/model/policy_op.py
index 7ef171da..a05f765e 100644
--- a/casbin/model/policy_op.py
+++ b/casbin/model/policy_op.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import enum
 
 
diff --git a/casbin/persist/__init__.py b/casbin/persist/__init__.py
index 0c04a1c4..78c13538 100644
--- a/casbin/persist/__init__.py
+++ b/casbin/persist/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .adapter import *
 from .adapter_filtered import *
 from .batch_adapter import *
diff --git a/casbin/persist/adapter.py b/casbin/persist/adapter.py
index 567bd770..0d291b3b 100644
--- a/casbin/persist/adapter.py
+++ b/casbin/persist/adapter.py
@@ -1,3 +1,18 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
+
 def load_policy_line(line, model):
     """loads a text line as a policy rule to model."""
 
diff --git a/casbin/persist/adapter_filtered.py b/casbin/persist/adapter_filtered.py
index 5cd1038c..dd3ab897 100644
--- a/casbin/persist/adapter_filtered.py
+++ b/casbin/persist/adapter_filtered.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .adapter import Adapter
 
 """ FilteredAdapter is the interface for Casbin adapters supporting filtered policies."""
diff --git a/casbin/persist/adapters/__init__.py b/casbin/persist/adapters/__init__.py
index 804ae9ca..5bee4fcf 100644
--- a/casbin/persist/adapters/__init__.py
+++ b/casbin/persist/adapters/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .file_adapter import FileAdapter
 from .adapter_filtered import FilteredAdapter
 from .update_adapter import UpdateAdapter
diff --git a/casbin/persist/adapters/adapter_filtered.py b/casbin/persist/adapters/adapter_filtered.py
index b37a0da0..571ee7d1 100644
--- a/casbin/persist/adapters/adapter_filtered.py
+++ b/casbin/persist/adapters/adapter_filtered.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin import persist
 from casbin import model
 from .file_adapter import FileAdapter
diff --git a/casbin/persist/adapters/file_adapter.py b/casbin/persist/adapters/file_adapter.py
index 8dc8d667..0e807598 100644
--- a/casbin/persist/adapters/file_adapter.py
+++ b/casbin/persist/adapters/file_adapter.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from casbin import persist
 import os
 
diff --git a/casbin/persist/adapters/update_adapter.py b/casbin/persist/adapters/update_adapter.py
index b9356ec6..590c1891 100644
--- a/casbin/persist/adapters/update_adapter.py
+++ b/casbin/persist/adapters/update_adapter.py
@@ -1,3 +1,18 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
+
 class UpdateAdapter:
     """UpdateAdapter is the interface for Casbin adapters with add update policy function."""
 
diff --git a/casbin/persist/batch_adapter.py b/casbin/persist/batch_adapter.py
index 8ccec0f3..c6688163 100644
--- a/casbin/persist/batch_adapter.py
+++ b/casbin/persist/batch_adapter.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .adapter import Adapter
 
 """BatchAdapter is the interface for Casbin adapters with multiple add and remove policy functions."""
diff --git a/casbin/persist/dispatcher.py b/casbin/persist/dispatcher.py
index 6ea589c1..51aa4a86 100644
--- a/casbin/persist/dispatcher.py
+++ b/casbin/persist/dispatcher.py
@@ -1,3 +1,18 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
+
 class Dispatcher:
     """Dispatcher is the interface for pycasbin dispatcher"""
 
diff --git a/casbin/rbac/__init__.py b/casbin/rbac/__init__.py
index cd3c1521..b82b0732 100644
--- a/casbin/rbac/__init__.py
+++ b/casbin/rbac/__init__.py
@@ -1 +1,15 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .role_manager import RoleManager
diff --git a/casbin/rbac/default_role_manager/__init__.py b/casbin/rbac/default_role_manager/__init__.py
index bf5c0470..45e45fde 100644
--- a/casbin/rbac/default_role_manager/__init__.py
+++ b/casbin/rbac/default_role_manager/__init__.py
@@ -1 +1,15 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .role_manager import RoleManager, DomainManager
diff --git a/casbin/rbac/default_role_manager/role_manager.py b/casbin/rbac/default_role_manager/role_manager.py
index c7e0ce7b..e6c7cbd6 100644
--- a/casbin/rbac/default_role_manager/role_manager.py
+++ b/casbin/rbac/default_role_manager/role_manager.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import logging
 from collections import namedtuple
 from enum import Enum
diff --git a/casbin/rbac/role_manager.py b/casbin/rbac/role_manager.py
index 9c1cefc4..09153e7a 100644
--- a/casbin/rbac/role_manager.py
+++ b/casbin/rbac/role_manager.py
@@ -1,3 +1,18 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
+
 class RoleManager:
     """provides interface to define the operations for managing roles."""
 
diff --git a/casbin/synced_enforcer.py b/casbin/synced_enforcer.py
index c1180360..716e9680 100644
--- a/casbin/synced_enforcer.py
+++ b/casbin/synced_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import threading
 import time
 
diff --git a/casbin/util/__init__.py b/casbin/util/__init__.py
index 92b6317c..f1cb7fab 100644
--- a/casbin/util/__init__.py
+++ b/casbin/util/__init__.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from .builtin_operators import *
 from .expression import *
 from .util import *
diff --git a/casbin/util/builtin_operators.py b/casbin/util/builtin_operators.py
index cf478864..5541974a 100644
--- a/casbin/util/builtin_operators.py
+++ b/casbin/util/builtin_operators.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import ipaddress
 import re
 
diff --git a/casbin/util/expression.py b/casbin/util/expression.py
index 6f519c63..350f6f11 100644
--- a/casbin/util/expression.py
+++ b/casbin/util/expression.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from simpleeval import EvalWithCompoundTypes
 import ast
 
diff --git a/casbin/util/rwlock.py b/casbin/util/rwlock.py
index 105312e1..0c0355df 100644
--- a/casbin/util/rwlock.py
+++ b/casbin/util/rwlock.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from threading import RLock, Condition
 
 # This implementation was adapted from https://en.wikipedia.org/wiki/Readers%E2%80%93writer_lock
diff --git a/casbin/util/util.py b/casbin/util/util.py
index 3003af67..9b817604 100644
--- a/casbin/util/util.py
+++ b/casbin/util/util.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from collections import OrderedDict
 import re
 
diff --git a/setup.py b/setup.py
index 86fb8896..d13f3b9f 100644
--- a/setup.py
+++ b/setup.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import setuptools
 from os import path
 
diff --git a/tests/__init__.py b/tests/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/benchmarks/__init__.py b/tests/benchmarks/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/benchmarks/__init__.py
+++ b/tests/benchmarks/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/benchmarks/benchmark_model.py b/tests/benchmarks/benchmark_model.py
index e0b54fae..5fb17a16 100644
--- a/tests/benchmarks/benchmark_model.py
+++ b/tests/benchmarks/benchmark_model.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import os
 import casbin
 
diff --git a/tests/config/__init__.py b/tests/config/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/config/__init__.py
+++ b/tests/config/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/config/test_config.py b/tests/config/test_config.py
index c7413f93..96c41bec 100644
--- a/tests/config/test_config.py
+++ b/tests/config/test_config.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import os
 from casbin.config import Config
 from unittest import TestCase
diff --git a/tests/model/__init__.py b/tests/model/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/model/__init__.py
+++ b/tests/model/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/model/test_policy.py b/tests/model/test_policy.py
index 757c9e53..855eb841 100644
--- a/tests/model/test_policy.py
+++ b/tests/model/test_policy.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from unittest import TestCase
 
 from casbin.model import Model
diff --git a/tests/rbac/__init__.py b/tests/rbac/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/rbac/__init__.py
+++ b/tests/rbac/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/rbac/test_role_manager.py b/tests/rbac/test_role_manager.py
index 8c3fe929..9e0327ef 100644
--- a/tests/rbac/test_role_manager.py
+++ b/tests/rbac/test_role_manager.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from unittest import TestCase
 from casbin.rbac import default_role_manager
 from casbin.util import regex_match_func
diff --git a/tests/test_distributed_api.py b/tests/test_distributed_api.py
index 9704dab6..84ef9900 100644
--- a/tests/test_distributed_api.py
+++ b/tests/test_distributed_api.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import casbin
 from tests.test_enforcer import get_examples, TestCaseBase
 
diff --git a/tests/test_enforcer.py b/tests/test_enforcer.py
index 284c8756..45f9022c 100644
--- a/tests/test_enforcer.py
+++ b/tests/test_enforcer.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import os
 import time
 from unittest import TestCase
diff --git a/tests/test_filter.py b/tests/test_filter.py
index 72dfce54..6633b229 100644
--- a/tests/test_filter.py
+++ b/tests/test_filter.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import casbin
 from unittest import TestCase
 from tests.test_enforcer import get_examples
diff --git a/tests/test_frontend.py b/tests/test_frontend.py
index 8ffdf73b..cfe1f6cb 100644
--- a/tests/test_frontend.py
+++ b/tests/test_frontend.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import json
 import re
 import casbin
diff --git a/tests/test_management_api.py b/tests/test_management_api.py
index 812c769e..7bcfcd2b 100644
--- a/tests/test_management_api.py
+++ b/tests/test_management_api.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from functools import partial
 
 import casbin
diff --git a/tests/test_rbac_api.py b/tests/test_rbac_api.py
index 01d21492..62c18b30 100644
--- a/tests/test_rbac_api.py
+++ b/tests/test_rbac_api.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 import casbin
 from tests.test_enforcer import get_examples, TestCaseBase
 
diff --git a/tests/util/__init__.py b/tests/util/__init__.py
index e69de29b..dcfb1ee3 100644
--- a/tests/util/__init__.py
+++ b/tests/util/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
diff --git a/tests/util/test_builtin_operators.py b/tests/util/test_builtin_operators.py
index 533861c2..e981f8e8 100644
--- a/tests/util/test_builtin_operators.py
+++ b/tests/util/test_builtin_operators.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from unittest import TestCase
 from casbin import util
 
diff --git a/tests/util/test_rwlock.py b/tests/util/test_rwlock.py
index f7309f8f..d4a248a6 100644
--- a/tests/util/test_rwlock.py
+++ b/tests/util/test_rwlock.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from unittest import TestCase
 from casbin.util.rwlock import RWLockWrite
 from concurrent.futures import ThreadPoolExecutor
diff --git a/tests/util/test_util.py b/tests/util/test_util.py
index 0b4be0e4..c60ff230 100644
--- a/tests/util/test_util.py
+++ b/tests/util/test_util.py
@@ -1,3 +1,17 @@
+# Copyright 2021 The casbin Authors. All Rights Reserved.
+#
+# 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.
+
 from unittest import TestCase
 from casbin import util