[Python] fix tags with underscore for python (#3995)

* fix tag with underscore for python

* remove log

samples/client/petstore/python/test/test_fake_classname_tags_123_api.py

@@ -0,0 +1,55 @@
+# coding: utf-8
+
+"""
+    Swagger Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+
+    OpenAPI spec version: 1.0.0
+    Contact: apiteam@swagger.io
+    Generated by: https://github.com/swagger-api/swagger-codegen.git
+
+    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 __future__ import absolute_import
+
+import os
+import sys
+import unittest
+
+import petstore_api
+from petstore_api.rest import ApiException
+from petstore_api.apis.fake_classname_tags_123_api import FakeClassnameTags123Api
+
+
+class TestFakeClassnameTags123Api(unittest.TestCase):
+    """ FakeClassnameTags123Api unit test stubs """
+
+    def setUp(self):
+        self.api = petstore_api.apis.fake_classname_tags_123_api.FakeClassnameTags123Api()
+
+    def tearDown(self):
+        pass
+
+    def test_test_classname(self):
+        """
+        Test case for test_classname
+
+        To test class name in snake case
+        """
+        pass
+
+
+if __name__ == '__main__':
+    unittest.main()