public function rules()
 {
     $rules = parent::rules();
     $rules[] = ['subject, html, from_email, to', 'required'];
     $rules[] = [implode(',', array_keys($this->getAttributes())), 'safe'];
     return $rules;
 }
 public function rules()
 {
     $rules = parent::rules();
     $rules[] = ['name, type, content', 'required'];
     $rules[] = [implode(',', array_keys($this->getAttributes())), 'safe'];
     return $rules;
 }