public function addExtraClasses($classes)
    {
        if (!is_array($classes)) {
            $classes = explode(" ", $classes);
        }

        $this->extra_classes = array_merge(
            $this->extra_classes,
            $classes
        );

        return $this;
    }
public function addExtraClasses($classes)
    {
        if (!is_array($classes)) {
            $classes = explode(" ", $classes);
        }

        $this->extra_classes = array_merge(
            $this->extra_classes,
            $classes
        );

        return $this;
    }
public function addExtraClasses ( $ classes ) { if ( ! is_array ( $ classes ) ) { $ classes = explode ( " " , $ classes ) ; } $ this -> extra_classes = array_merge ( $ this -> extra_classes , $ classes ) ; return $ this ; }
Add additional css classes

@param  array|string  $extra_classes  extra CSS classes

@return  self
Add additional css classes