public function icon($icon = null)
    {
        if ($icon === null) {
            return $this->_icon;
        }
        $this->_icon = $icon;

        return $this;
    }
public function icon($icon = null)
    {
        if ($icon === null) {
            return $this->_icon;
        }
        $this->_icon = $icon;

        return $this;
    }
public function icon ( $ icon = null ) { if ( $ icon === null ) { return $ this -> _icon ; } $ this -> _icon = $ icon ; return $ this ; }
Get or set the icon class.

@param null|string $icon
@return MenuItem|string
Get or set the icon class .