public static function createFromDateInterval(\DateInterval $interval)
 {
     $obj = new self('PT0S');
     foreach ($interval as $property => $value) {
         if ($property == "days") {
             if ($value != -99999) {
                 $obj->monthDays = $value;
             }
         } else {
             $obj->{$property} = $value;
         }
     }
     $obj->calculateTotals();
     return $obj;
 }