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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(cls, key):
 """Retrieve a fake Weld input. Evaluate its intermediate result dependency if not yet done. Parameters key : str Weld input name previously obtained through create_fake_array_input. Returns ------- numpy.ndarray or tuple The corresponding data. """

        assert isinstance(key, str)

        data = cls._cache[key]
        if isinstance(data, _FakeWeldInput):
            data = data.retrieve()

        cls._cache[key] = data

        return data