code: def update_get_params(self):
          
          if isinstance(self._fields, (tuple, list)):  # tuples & lists > x,y,z
              self.get_params["fields"] = ",".join([str(_) for _ in self._fields])
          elif isinstance(self._fields, str):
              self.get_params["fields"] = self._fields
docs: Update HTTP GET params with the given fields that user wants to fetch.