Entry point to the execution of the program.

def execute(self):
        """
        Entry point to the execution of the program.
        """
        # Ensure that we have commands registered
        if not self.commands or self._parser is None:
            raise NotImplementedError(
                "No commands registered with this program!"
            )

        # Handle input from the command line
        args = self.parser.parse_args()                # Parse the arguments

        try:

            handle_default_args(args)                  # Handle the default args

            if not hasattr(args, 'func'):              # Handle no subcommands
                self.parser.print_help()
                self.exit(0)

            msg = args.func(args)                      # Call the default function
            msg = "{}\n".format(msg) if msg else ''    # Format the message
            self.exit(0, msg)                          # Exit cleanly with message

        except Exception as e:
            if hasattr(args, 'traceback') and args.traceback:
                traceback.print_exc()

            msg = color.format(str(e), color.RED)
            self.exit(1, msg)