public function equals(AclTargetIdentityInterface $identity)
 {
     return $identity->getClassName() === $this->getClassName() && $identity->getObjectIdentifier() === $this->getObjectIdentifier() && $identity->getFieldName() === $this->getFieldName();
 }
 protected function hasBeenVisited(AclTargetIdentity $target, array &$visited)
 {
     return isset($visited[$this->getKeyForIdentityPart($target->getClassName())][$this->getKeyForIdentityPart($target->getObjectIdentifier())][$this->getKeyForIdentityPart($target->getFieldName())]);
 }