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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 packageDescriptor(self, dir=os.getcwd(), args=[]):
 		""" 		Packages a build of the Unreal project or plugin in the specified directory 		"""

		
		# Verify that an Unreal project or plugin exists in the specified directory
		descriptor = self.getDescriptor(dir)
		
		# Perform the packaging step
		if self.isProject(descriptor):
			self.packageProject(dir, args[0] if len(args) > 0 else 'Shipping', args[1:])
		else:
			self.packagePlugin(dir, args)