public static boolean checkGroup(LuckPermsPlugin plugin, Sender sender, PermissionHolder holder, ContextSet contextSet) {
        if (holder.getType() == HolderType.GROUP) {
            return checkGroup(plugin, sender, ((Group) holder).getName(), contextSet);
        }
        return false;
    }
Checks if the sender has permission to act using a given group, if holder is a group.

@param plugin the plugin instance
@param sender the sender to check
@param holder the target group (doesn't have to be a group instance - this method checks that)
@param contextSet the contexts the sender is trying to act within
@return true if the sender should NOT be allowed to act, true if they should
common/src/main/java/me/lucko/luckperms/common/command/access/ArgumentPermissions.java