code: def print_label(self, package_num=None):
          
  
          if package_num:
              packages = [
                  self.shipment.response.CompletedShipmentDetail.CompletedPackageDetails[package_num]
              ]
          else:
              packages = self.shipment.response.CompletedShipmentDetail.CompletedPackageDetails
  
          for package in packages:
              label_binary = binascii.a2b_base64(package.Label.Parts[0].Image)
              self._print_base64(label_binary)
docs: Prints all of a shipment's labels, or optionally just one.
          
          @type package_num: L{int}
          @param package_num: 0-based index of the package to print. This is
                              only useful for shipments with more than one package.