public function removeBlankOptions($haystack)
    {
        foreach ($haystack as $key => $value) {
            if (is_array($value)) {
                $haystack[$key] = $this->removeBlankOptions($haystack[$key]);
            }
            if ((is_array($haystack[$key]) && empty($haystack[$key])) || (is_string($haystack[$key]) && !strlen($haystack[$key]))) {
                unset($haystack[$key]);
            }
        }
        return $haystack;
    }