def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def execute_as(self, user):
        self.check_prereq(self.LOGGED_IN)
        self._exit_modes_beyond(self.LOGGED_IN)
        user.commandLine(self)
        user.login()
        self.modeList.append(user)
        return user