protected function buildIconClasses($icon)
    {
        //Prepends the string "fa-" to any other class
        $icon = preg_replace('/(?<![^ ])(?=[^ ])(?!fa)/', 'fa-', $icon);
        $icon = !is_array($icon) ? preg_split('/\s+/', $icon, -1, PREG_SPLIT_NO_EMPTY) : $icon;

        //Adds the "fa" class, if no other "basic" class is present
        if (!count(array_intersect(['fa', 'fab', 'fal', 'far', 'fas'], $icon))) {
            array_unshift($icon, 'fas');
        }

        return implode(' ', array_unique($icon));
    }