code: def query(self):
          
          query_context = QueryContext(**json.loads(request.form.get('query_context')))
          security_manager.assert_datasource_permission(query_context.datasource)
          payload_json = query_context.get_payload()
          return json.dumps(
              payload_json,
              default=utils.json_int_dttm_ser,
              ignore_nan=True,
          )
docs: Takes a query_obj constructed in the client and returns payload data response
          for the given query_obj.
          params: query_context: json_blob