public function getLastEvent()
    {
        if (null === $this->{self::$sequence[0]}) {
            return self::$sequence[0];
        }

        foreach (self::$sequence as $i => $event) {
            if (null === $this->$event) {
                return self::$sequence[$i-1];
            }
        }

        return self::$sequence[count(self::$sequence)-1];
    }