Class EzSystems\EzPlatformPageFieldType\FieldType\LandingPage\Model\Page contains method getZoneByIdentifier() which has invalid return type.

Steps to reproduce:
Create new EzSystems\EzPlatformPageFieldType\FieldType\LandingPage\Model\Page object anywhere and call getZoneByIdentifier with no existing zone id attribute.

        $page = new \EzSystems\EzPlatformPageFieldType\FieldType\LandingPage\Model\Page();
        $page->getZoneByIdentifier(55);

Result
Throws 500 exception