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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def modifyStopOrder(self, orderId, parentId, newStop, quantity, transmit=True, account=None):
 """ modify stop order """

        if orderId in self.orders.keys():
            order = self.createStopOrder(
                quantity = quantity,
                parentId = parentId,
                stop     = newStop,
                trail    = False,
                transmit = transmit,
                account  = account
            )
            return self.placeOrder(self.orders[orderId]['contract'], order, orderId)

        return None