code: def _exception_for(self, code):
          
          if code in self.errors:
              return self.errors[code]
          elif 500 <= code < 599:
              return exceptions.RemoteServerError
          else:
              return exceptions.UnknownError
docs: Return the exception class suitable for the specified HTTP
          status code.
  
          Raises:
              UnknownError: The HTTP status code is not one of the knowns.