old_contents: import responses
  
  
  class AuthenticationTestMixin(object):
      """ Mixin for testing authentication. """
      def setUp(self):
          super(AuthenticationTestMixin, self).setUp()
          responses.reset()
  
      def _mock_auth_api(self, url, status, body=None):
          body = body or {}
          responses.add(
              responses.POST,
              url,
              status=status,
              json=body,
              content_type='application/json'
          )
  
new_contents: import responses
  
  
  class AuthenticationTestMixin:
      """ Mixin for testing authentication. """
      def setUp(self):
          super(AuthenticationTestMixin, self).setUp()
          responses.reset()
  
      def _mock_auth_api(self, url, status, body=None):
          body = body or {}
          responses.add(
              responses.POST,
              url,
              status=status,
              json=body,
              content_type='application/json'
          )
  
subject: Fix new lint errors now that we've dropped python 2 support.