def get_mandate_action(self):
        """
        return an action for an ext.mandate contains into the domain a
        specific tuples to get concerned mandates
        """
        self.ensure_one()
        res_ids = self._get_assemblies()._get_mandates().ids
        domain = [("id", "in", res_ids)]

        # get model's action to update its domain
        action = self.env["ir.actions.act_window"]._for_xml_id(
            "mozaik_mandate.ext_mandate_action"
        )
        action["domain"] = domain
        return action