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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 get_method(self, name, descriptor):
 """ Get the method by name and descriptor, or create a new one if the requested method does not exists. :param name: method name :param descriptor: method descriptor, for example `'(I)V'` :return: :class:`ExternalMethod` """

        key = name + str(descriptor)
        if key not in self.methods:
            self.methods[key] = ExternalMethod(self.name, name, descriptor)

        return self.methods[key]