public function addAttribute($key, $value = null)
    {
        $this->element->addAttribute($key, $value);

        return $this;
    }
public function addAttribute($key, $value = null)
    {
        $this->element->addAttribute($key, $value);

        return $this;
    }
public function addAttribute ( $ key , $ value = null ) { $ this -> element -> addAttribute ( $ key , $ value ) ; return $ this ; }
Add attribute on element

@param string $key
@param string $value

@return $this
Add attribute on element