def remove(self, key):
        """Remove the keyed message; raise KeyError if it doesn't exist."""
        _singlefileMailbox.remove(self, key)
        if key == self._labels:
            del self._labels[key]
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/Babyl.remove/operator `in` -> `==`