how to return value in new record to odoo code example

Example: how to return value in new record to odoo

def computeremainingFeeds(self):
        for rec in self:
            if rec.feed_received_kg != 0:
                rec.remaining_feed_credit = rec.feed_received_kg - rec.feed_consumed_kg
            elif rec.remaining_feed_credit != 0:
                rec.remaining_feed_credit = rec.remaining_feed_credit - rec.feed_consumed_kg
        return remaining_feed_credit