code: def _set_named_args(self, **kv):
          
          for k in kv:
              self._body['${0}'.format(k)] = kv[k]
          return self
docs: Set a named parameter in the query. The named field must
          exist in the query itself.
  
          :param kv: Key-Value pairs representing values within the
              query. These values should be stripped of their leading
              `$` identifier.