public static function instance(DateInterval $di)
{
if (static::wasCreatedFromDiff($di)) {
throw new InvalidArgumentException("Can not instance a DateInterval object created from DateTime::diff().");
}
$instance = new static($di->y, $di->m, 0, $di->d, $di->h, $di->i, $di->s);
$instance->invert = $di->invert;
$instance->days = $di->days;
return $instance;
}