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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 update(self, key, item):
 """ Update item into hash table with specified key and item. If key is already present, destroys old item and inserts new one. Use free_fn method to ensure deallocator is properly called on item. """

        return lib.zhash_update(self._as_parameter_, key, item)