How to use the adal.oauth2_client.OAuth2Client function in adal

def create_oauth2_client_stub(self, authority, token_response, err):
            authorityObject = Authority(authority, False)
            authorityObject.token_endpoint = AADConstants.TOKEN_ENDPOINT_PATH
            authorityObject.device_code_endpoint = AADConstants.DEVICE_ENDPOINT_PATH
            client = OAuth2Client(cp['callContext'], authorityObject)

            def side_effect (oauth):
                return token_response
            client.get_token = mock.MagicMock(side_effect=side_effect)

            return client

def test_api_version_is_set(self):
        client = adal.oauth2_client.OAuth2Client(
            {"api_version": "1.0", "log_context": mock.Mock()}, self.authority)
        self.assertIn('api-version=1.0', client._create_token_url().geturl())

def _create_oauth2_client(self):
        return oauth2_client.OAuth2Client(self._call_context, 
                                          self._authentication_context.authority)

def _create_oauth2_client(self):
        return oauth2_client.OAuth2Client(
            self._call_context,
            self._authentication_context.authority)