public function getClasses()
    {
        $classes = [];
        $sizes = $this->sizes;
        if (isset($sizes['phone'])) {
            $classes[] = 'col-xs-' . $sizes['phone'];
        }
        if (isset($sizes['tablet'])) {
            $classes[] = 'col-sm-' . $sizes['tablet'];
        }
        if (isset($sizes['mediumDesktop'])) {
            $classes[] = 'col-md-' . $sizes['mediumDesktop'];
        }
        if (isset($sizes['largeDesktop'])) {
            $classes[] = 'col-lg-' . $sizes['largeDesktop'];
        }

        return implode(' ', $classes);
    }