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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 remove_key(self, store_key):
 """Remove key from the index. :param store_key: The key for the document in the store :type store_key: str """

        if store_key in self._undefined_keys:
            del self._undefined_keys[store_key]
        if store_key in self._reverse_index:
            for value in self._reverse_index[store_key]:
                self._index[value].remove(store_key)
            del self._reverse_index[store_key]