async def variant(self, elem=None, elem_type=None, params=None, wrapped=None):
        """
        Loads/dumps variant type
        :param elem:
        :param elem_type:
        :param params:
        :return:
        """
        elem_type = elem_type if elem_type else elem.__class__
        if hasattr(elem_type, "serialize_archive"):
            elem = elem_type() if elem is None else elem
            return await elem.serialize_archive(
                self, elem=elem, elem_type=elem_type, params=params
            )

        if self.writing:
            return await self._dump_variant(
                self.iobj,
                elem=elem,
                elem_type=elem_type if elem_type else elem.__class__,
                params=params,
            )
        else:
            return await self._load_variant(
                self.iobj,
                elem_type=elem_type if elem_type else elem.__class__,
                params=params,
                elem=elem,
                wrapped=wrapped,
            )
Loads/dumps variant type
        :param elem:
        :param elem_type:
        :param params:
        :return: