old_contents: class ResponseError(Exception):
      def __init__(self, *args, code=None, **kwargs):
          self.code = code
          super().__init__(*args, **kwargs)
  
new_contents: class ResponseError(Exception):
      """For throwing in case of a non-200 response status."""
      def __init__(self, *args, code=None, **kwargs):
          self.code = code
          super().__init__(*args, **kwargs)
  
subject: Add docstrings