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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 add_package(self, package_item):
 """ Adds a package to the ship request. @type package_item: WSDL object, type of RequestedPackageLineItem WSDL object. @keyword package_item: A RequestedPackageLineItem, created by calling create_wsdl_object_of_type('RequestedPackageLineItem') on this ShipmentRequest object. See examples/create_shipment.py for more details. """


        self.RequestedShipment.RequestedPackageLineItems.append(package_item)
        package_weight = package_item.Weight.Value
        self.RequestedShipment.TotalWeight.Value += package_weight
        self.RequestedShipment.PackageCount += 1