def remove(self, key):
if self.prepickle:<EOL><INDENT>key = pickle.dumps(key)<EOL><DEDENT>if key not in self.keys:<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>for H, hashtable in zip(self.keys[key], self.hashtables):<EOL><INDENT>hashtable.remove_val(H, key)<EOL>if not hashtable.get(H):<EOL><INDENT>hashtable.remove(H)<EOL><DEDENT><DEDENT>self.keys.remove(key)<EOL>
Remove the key from the index.

Args:
    key (hashable): The unique identifier of a set.