Check if the object that contains the ezpaex attribute is an user

@return bool if the contentobject is a user or not
504417
function isUser()
	{
		$ezpo = eZPersistentObject::fetchObject( eZContentObject::definition(),
                                                null,
                                                array( 'id' => $this->attribute('contentobject_id') ),
                                                true );
		return eZUser::isUserObject( $ezpo );
	}
244286
static function fetchByUserIdentifier( $userIdentifier, $contentObjectID = false, $asObject = true )
    {
        $conditions = array( 'user_identifier' => $userIdentifier );
        if ( $contentObjectID )
            $conditions['contentobject_id'] = $contentObjectID;
        return eZPersistentObject::fetchObject( eZInformationCollection::definition(),
                                                null,
                                                $conditions,
                                                $asObject );
    }
1145148
public static function getCanPurge(): bool
    {
        if (!isset(self::$canPurge)) {
            /** @var ConfigModel $settings */
            $config = ImagerService::getConfig();
            
            // No Imgix config, no purging
            $imgixConfigArr = $config->getSetting('imgixConfig');
            if (!$imgixConfigArr || !\is_array($imgixConfigArr) || empty($imgixConfigArr)) {
                self::$canPurge = false;
                return false;
            }
            
            // Make sure there's at least one profile that is not a web proxy and that is not excluded from purging
            $hasApiKey = !!$config->getSetting('imgixApiKey');
            $hasPurgableProfile = false;
            foreach ($imgixConfigArr as $profile => $imgixConfig) {
                $imgixConfig = new ImgixSettings($imgixConfig);
                $hasApiKey = $hasApiKey || !!$imgixConfig->apiKey;
                $hasPurgableProfile = $hasPurgableProfile || (!$imgixConfig->sourceIsWebProxy && !$imgixConfig->excludeFromPurge);
                if ($hasApiKey && $hasPurgableProfile) {
                    break;
                }
            }
            
            self::$canPurge = $hasApiKey && $hasPurgableProfile;
        }
        
        return self::$canPurge;
    }
275745
private function isDeletingFile( eZHTTPTool $http, eZContentObjectAttribute $contentObjectAttribute )
    {
        $isDeletingFile = false;
        if ( $http->hasPostVariable( 'CustomActionButton' ) )
        {
            $customActionArray = $http->postVariable( 'CustomActionButton' );
            $attributeID = $contentObjectAttribute->attribute( 'id' );
            if ( isset( $customActionArray[$attributeID . '_delete_binary'] ) )
            {
                $isDeletingFile = true;
            }
        }

        return $isDeletingFile;
    }
518582
public function isAuthorised()
    {

        if (is_array($this->user) === true
            && isset($this->user['error']) === false
        ) {

            return true;
        }

        return $this->getUser();
    }
831898
private static boolean hasSomeUser() {
        for (User u : User.getAll())
            if(u.getProperty(Details.class)!=null)
                return true;
        return false;
    }
345860
public function match(){

            $session = $this->getSession();
            $key = static::USER_SESSION;
            if($session->has($key)){

                if($value = $session->get($key) instanceof AuthenticationLoginObject){
                    return $value;
                }
            }else{
                return false;
            }
        }
269041
public function isWritableByCurrentUser()
    {
        if ($this->hasConfigValue()) {
            return false;
        }

        if (isset($this->hasWritePermission)) {
            return $this->hasWritePermission;
        }

        // performance improvement, do not detect this in __construct otherwise likely rather "big" query to DB.
        $this->hasWritePermission = Piwik::hasUserSuperUserAccess();

        return $this->hasWritePermission;
    }
182864
protected function validateEmailExistsUser()
    {
        $field = 'email';
        $value = $this->getSubmitted($field);

        if ($this->isError($field) || !isset($value)) {
            return null;
        }

        $user = $this->user->getByEmail($value);

        if (empty($user['status'])) {
            $this->setErrorUnavailable($field, $this->translation->text('E-mail'));
            return false;
        }

        $this->setSubmitted($field, $user);
        return true;
    }
1025224
public static function isAuthenticatedProxy()
    {
        $proxyUser = self::$global->getProxyUser();
        $proxyPwd = self::$global->getProxyPassword();
        return !empty($proxyUser) && !empty($proxyPwd);
    }
1373753
public function getIPaymentUser()
    {
        if ($this->_sIPaymentUser === null) {
            $this->_sIPaymentUser = false;
            $this->_sIPaymentUser = \OxidEsales\Eshop\Core\Registry::getConfig()->getConfigParam('iShopID_iPayment_User');
        }

        return $this->_sIPaymentUser;
    }
409934
protected function wasActualUser()
    {
        return $this->wrappedObject->user_id == $this->wrappedObject->revisionable_id || !$this->wrappedObject->user_id;
    }
536793
public function hasObjectAttributeContent( $contentObjectAttribute )
    {
        /** @var $eZTags eZTags */
        $eZTags = $contentObjectAttribute->content();
        if ( !$eZTags instanceof eZTags )
            return false;

        $tagsCount = $eZTags->attribute( 'tags_count' );
        return $tagsCount > 0;
    }
762541
public static function checkBrowserYandex()
    {
        if (stripos(self::$userAgentString, 'YaBrowser') !== false) {
            $aresult = explode('/', stristr(self::$userAgentString, 'YaBrowser'));
            if (isset($aresult[1])) {
                $aversion = explode(' ', $aresult[1]);
                self::$browser->setVersion($aversion[0]);
            }
            self::$browser->setName(Browser::YANDEX);

            return true;
        }

        return false;
    }
202805
public function isMainUser()
    {
        $user = $this->getUser();
        if ($user->getIsGuest()) {
            return true;
        }
        return ($user->getId() === $this->getMainUser()->getId());
    }
481323
public function canEditAuthors($member = null)
    {
        $member = $this->getMember($member);

        $extended = $this->extendedCan('canEditAuthors', $member);

        if ($extended !== null) {
            return $extended;
        }

        $parent = $this->Parent();

        if ($parent instanceof Blog && $parent->exists()) {
            if ($parent->isEditor($member)) {
                return true;
            }

            if ($parent->isWriter($member) && $this->isAuthor($member)) {
                return true;
            }
        }

        return Permission::checkMember($member, Blog::MANAGE_USERS);
    }
292076
public function isOwner( $user = NULL )
	{
		$user	= $user ? $user : get_current_user();
		if( !function_exists( 'posix_getpwuid' ) )
			return TRUE;
		$uid	= fileowner( $this->fileName );
		if( !$uid )
			return TRUE;
		$owner	= posix_getpwuid( $uid );
		if( !$owner )
			return TRUE;
		print_m( $owner );
		return $user == $owner['name'];
	}