public UUID getUserTarget(int index, LuckPermsPlugin plugin, Sender sender) {
        String arg = get(index);
        return UserParentCommand.parseTargetUniqueId(arg, plugin, sender);
    }
A list of {@link String} arguments, with extra methods to help
with parsing.
common/src/main/java/me/lucko/luckperms/common/command/utils/ArgumentList.java