def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def encode(self):
        return {
            'af': ip_address(self.gaddr).vapi_af,
            'grp_address': {
                ip_address(self.gaddr).vapi_af_name: self.gaddr
            },
            'src_address': {
                ip_address(self.saddr).vapi_af_name: self.saddr
            },
            'grp_address_length': self.glen,
        }