diff --git a/tests/unit/containers/cls/__init__.py b/tests/unit/containers/cls/__init__.py
new file mode 100644
index 00000000..ff13b5c1
--- /dev/null
+++ b/tests/unit/containers/cls/__init__.py
@@ -0,0 +1 @@
+"""Container class tests."""
diff --git a/tests/unit/containers/instance/test_custom_strings_py2_py3.py b/tests/unit/containers/instance/test_custom_strings_py2_py3.py
index 04692798..45cc451d 100644
--- a/tests/unit/containers/instance/test_custom_strings_py2_py3.py
+++ b/tests/unit/containers/instance/test_custom_strings_py2_py3.py
@@ -25,23 +25,23 @@ def provider():
     return providers.Provider()
 
 
-def test_setattr(container: containers.DynamicContainer, provider: providers.Provider):
+def test_setattr(container, provider):
     setattr(container, CustomString("test_attr"), provider)
     assert container.test_attr is provider
 
 
-def test_delattr(container: containers.DynamicContainer, provider: providers.Provider):
+def test_delattr(container, provider):
     setattr(container, CustomString("test_attr"), provider)
     delattr(container, CustomString("test_attr"))
     with raises(AttributeError):
         container.test_attr
 
 
-def test_set_provider(container: containers.DynamicContainer, provider: providers.Provider):
+def test_set_provider(container, provider):
     container.set_provider(CustomString("test_attr"), provider)
     assert container.test_attr is provider
 
 
-def test_set_providers(container: containers.DynamicContainer, provider: providers.Provider):
+def test_set_providers(container, provider):
     container.set_providers(**{CustomString("test_attr"): provider})
     assert container.test_attr is provider