src/Time.php
public static function cast($time)
    {
        return $time instanceof self ?
                $time :
                new self($time->format(self::ISO8601), $time->getTimezone());
    }
public static function cast($time)
    {
        return $time instanceof self ?
                $time :
                new self($time->format(self::ISO8601), $time->getTimezone());
    }
Faz o "cast" de \DateTime para p13\datetime\Time
@param \DateTime $time
@return Time