public function getContentTypesByIdentifier($identifier)
    {
        if (strstr($identifier, ',')) {
            $contentTypeArray = explode(',', $identifier);
        } else {
            $contentTypeArray[] = $identifier;
        }

        $contentTypesCollection = array();
        foreach ($contentTypeArray as $contentTypeIdentifier) {
            if (!empty($contentTypeIdentifier)) {
                $contentTypesCollection[] = $this->contentTypeService->loadContentTypeByIdentifier($contentTypeIdentifier);
            }
        }

        return $contentTypesCollection;
    }