public static function lastWeek($timeZone = null, $startOfWeek = 0)
    {
        $now = null;
        $before = null;
        if ( is_null($timeZone) ) {
            $now = new \DateTime();
            $before = new \DateTime();
        } else {
            $now = new \DateTime( "now", new \DateTimeZone( $timeZone ) );
            $before = new \DateTime( "now", new \DateTimeZone( $timeZone ) );
        }
        $dayOfWeek = (int) $now->format( "w" );
        $offset = (($dayOfWeek - $startOfWeek ) + 7 ) % 7;
        $beginOffset = $offset + 7;
        $endOffset = $offset + 1;
        $before->modify( "-$beginOffset day" );
        $now->modify( "-$endOffset day" );
        $range = new Range( $before, $now );

        return $range;
    }