def do_exit(self, arg_list: List[str]) -> bool:
        """Exit the application with an optional exit code.

Usage:  exit [exit_code]
    Where:
        * exit_code - integer exit code to return to the shell
"""
        # If an argument was provided
        if arg_list:
            try:
                self.exit_code = int(arg_list[0])
            except ValueError:
                self.perror("{} isn't a valid integer exit code".format(arg_list[0]))
                self.exit_code = -1

        self._should_quit = True
        return self._STOP_AND_EXIT
Exit the application with an optional exit code.

Usage:  exit [exit_code]
    Where:
        * exit_code - integer exit code to return to the shell