Loads/dumps tuple
        :return:

async def tuple(self, elem=None, elem_type=None, params=None):
        """
        Loads/dumps tuple
        :return:
        """
        if hasattr(elem_type, 'blob_serialize'):
            container = elem_type() if elem is None else elem
            return await container.blob_serialize(self, elem=elem, elem_type=elem_type, params=params)

        if self.writing:
            return await self.dump_tuple(elem, elem_type, params)
        else:
            return await self.load_tuple(elem_type, params=params, elem=elem)