Why is it problem? Sorry for my bad english.
DeferredRegister argTypeRegistry = DeferredRegister.create(Registry.COMMAND_ARGUMENT_TYPE_REGISTRY, "flashnpc");
argTypeRegistry.register("quest", QuestArgument.class, new ArgumentType<>(QuestArgument::quest());
argTypeRegistry.register("npcfunction", NpcFunctionArgument.class, new ArgumentType<>(NpcFunctionArgument::function()));
Minecraft mod 1.19