'Return network representation of the start transaction message'

def to_network(self):

    return (self._message_id.trader_id, self._message_id.message_number, self._transaction_id.trader_id, self._transaction_id.transaction_number, self._order_id.trader_id, self._order_id.order_number, self._recipient_order_id.trader_id, self._recipient_order_id.order_number, self._proposal_id, self._price, self._quantity, self._timestamp)
