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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 empty(cls):
 """ Returns an empty set. An empty set is unbounded and only contain the empty set. True It is unbounded but the boundaries are not infinite. Its boundaries are returned as ``None``. Every set contains the empty set. """


        self = cls.__new__(cls)
        self._range = _empty_internal_range
        return self