public void hook() {
        this.hooked = true;
        this.permissible.hookedAttachments.add(this);
        for (Map.Entry<String, Boolean> entry : this.perms.entrySet()) {
            if (entry.getKey() == null || entry.getKey().isEmpty()) {
                continue;
            }
            setPermissionInternal(entry.getKey(), entry.getValue());
        }
    }
Hooks this attachment with the parent {@link User} instance.
bukkit/src/main/java/me/lucko/luckperms/bukkit/inject/permissible/LuckPermsPermissionAttachment.java