public static function fromJson($json)
 {
     $article = new Article();
     return $article->setId($json->Id)->setSlug($json->Slug)->setTitle($json->Title)->setSubtitle($json->SubTitle)->setTextFormatted($json->TextFormatted)->setCreatedOn(new \DateTime($json->CreatedOn))->setLastModificationDate(new \DateTime($json->LastModificationDate))->setRedactor(Person::fromJson($json->Redactor))->setCategory(Category::fromJson($json->Category));
 }