public function addMembers(array $members)
    {
        $members = array_map(function ($member) {
            return $member instanceof Model
                ? $member->getDn()
                : $member;
        }, $members);

        $mod = $this->newBatchModification(
            $this->schema->member(),
            LDAP_MODIFY_BATCH_ADD,
            $members
        );

        return $this->addModification($mod)->save();
    }