fix: remove six dependency (#120)

Author: rafilong

tests/unit/v1/test_async_collection.py

@@ -17,7 +17,6 @@
 import aiounittest
 
 import mock
-import six
 
 
 class MockAsyncIter:
@@ -46,7 +45,7 @@ def _get_public_methods(klass):
             *(
                 (
                     name
-                    for name, value in six.iteritems(class_.__dict__)
+                    for name, value in class_.__dict__.items()
                     if (
                         not name.startswith("_")
                         and isinstance(value, types.FunctionType)