code: static protected function getValidatorsForKey($key) {
          $validators = static::getValidatorsForScaffoldFormConfig();
          $validatorsForKey = [];
          foreach ($validators as $setting => $rules) {
              if (preg_match("%^{$key}($|\.)%", $setting)) {
                  $validatorsForKey[] = $rules;
              }
          }
          return $validatorsForKey;
      }
docs: Get all validators for specific key.
  Override this if you need some specific validation for keys that are not present in scaffold config form and
  can only be updated via static::update() method.
  @param string $key
  @return array