/**
  * Calculates timezone offset which needs to be added.
  *
  * @param Base\Model $resource Currently processed resource.
  *
  * @static
  * @access private
  *
  * @return void
  */
 private static function applyTimezoneEffect(Base\Model $resource)
 {
     foreach ($resource::timezoneAwareFields() as $datetime_field) {
         if ($resource->{$datetime_field}) {
             $resource->{$datetime_field} = Helpers\DateTime::format($resource->{$datetime_field});
         }
     }
 }