<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def modify_order_group(self, orderId, entry=None, target=None, stop=None, quantity=None):
 """Modify bracket order :Parameters: orderId : int the order id to modify :Optional: entry: float new entry limit price (for unfilled limit orders only) target: float new target limit price (for unfilled limit orders only) stop: float new stop limit price (for unfilled limit orders only) quantity : int the required quantity of the modified order """

        return self.parent.modify_order_group(self, orderId=orderId,
                                              entry=entry, target=target,
                                              stop=stop, quantity=quantity)