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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 contains(self, item):
 """ Determines whether this set contains the specified item or not. :param item: (object), the specified item to be searched. :return: (bool), ``true`` if the specified item exists in this set, ``false`` otherwise. """

        check_not_none(item, "Value can't be None")
        item_data = self._to_data(item)
        return self._encode_invoke(set_contains_codec, value=item_data)