public function id($id = null)
    {
        if (is_null($id)) {
            return $this->id;
        }

        $this->id = $id;

        return $this;
    }
public function id($id = null)
    {
        if (is_null($id)) {
            return $this->id;
        }

        $this->id = $id;

        return $this;
    }
public function id ( $ id = null ) { if ( is_null ( $ id ) ) { return $ this -> id ; } $ this -> id = $ id ; return $ this ; }
Set id for the item manually.

@param mixed $id

@return Item|int
Set id for the item manually .