def add(self, message):
        """Add message and return assigned key."""
        self._lookup()
        self._toc[self._next_key] = self._append_message(message)
        self._next_key += 1
        self._pending = True
        return self._next_key - 1
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/_singlefileMailbox.add/original