Yagnap

My command is in a seperate class and are registered in another class. I want to make a command that goes about like this: /modid commandname [argument] I also want the commandname to be in the autocomplete, so i use: public static ArgumentBuilder<CommandSource, ?> register(CommandDispatcher<CommandSource> dispatcher) { return Commands.literal("commandname") .requires(cs -> cs.hasPermissionLevel(0)) .executes(CMD); } CMD is a private static final Instance of the class of the Command. How can I get [argument]? Thank you in advance for any tips.