code: def comment_request(self, request_id, body, commit=None,
                          filename=None, row=None):
          
          request_url = ("{}pull-request/{}/comment"
                         .format(self.create_basic_url(), request_id))
  
          payload = {'comment': body}
          if commit is not None:
              payload['commit'] = commit
          if filename is not None:
              payload['filename'] = filename
          if row is not None:
              payload['row'] = row
  
          return_value = self._call_api(request_url,
                                        method='POST', data=payload)
  
          LOG.debug(return_value)
docs: Create a comment on the request.
          :param request_id: the id of the request
          :param body: the comment body
          :param commit: which commit to comment on
          :param filename: which file to comment on
          :param row: which line of code to comment on
          :return: