CommandAPICommand main = null;

main = new CommandAPICommand("main")
	.executes((sender, args) -> {
		System.out.println(main.getSubcommands().size());
	});

CommandAPICommand sub = new CommandAPICommand("sub")
	.executes((sender, args) -> {
		System.out.println("Subcommand called");
	});

main.withSubcommand(sub);
main.register();