python: Remove usage of six (#16675)

samples/openapi3/client/petstore/python-pydantic-v1/petstore_api/api/fake_classname_tags_123_api.py

@@ -14,9 +14,6 @@ from __future__ import absolute_import
 
 import re  # noqa: F401
 
-# python 2 and python 3 compatibility library
-import six
-
 from petstore_api.api_client import ApiClient
 from petstore_api.exceptions import (  # noqa: F401
     ApiTypeError,
@@ -119,7 +116,7 @@ class FakeClassnameTags123Api(object):
             ]
         )
 
-        for key, val in six.iteritems(local_var_params['kwargs']):
+        for key, val in local_var_params['kwargs'].items():
             if key not in all_params:
                 raise ApiTypeError(
                     "Got an unexpected keyword argument '%s'"

samples/openapi3/client/petstore/python-pydantic-v1/tests/test_api_exception.py

@@ -10,7 +10,6 @@ $ pytest
 """
 
 import os
-import six
 import sys
 import unittest
 

samples/openapi3/client/petstore/python-pydantic-v1/tests/test_api_validation.py

@@ -10,7 +10,6 @@ $ pytest
 """
 
 import os
-import six
 import sys
 import unittest