public function getOption($args = null, $prefix = null) {

        $result = null;
        $options = get_option($this->key);

        if (!Helper::isEmpty($prefix)) {
            $prefix .= '_';
            if (is_array($args)) {
                foreach ($args as $val) {
                    $key = $prefix.$val;
                    $result[$val] = Helper::isGood($options, $key) ? $options[$key] : null;
                }
            } else if (is_string($args)) {
                if ($args == 'all') {
                    foreach ($options as $key=>$val) {
                        if (strpos($key, $prefix) !== false) {
                            $result[str_replace($prefix, '', $key)] = Helper::isGood($options, $key) ? $options[$key] : null;
                        }
                    }
                } else {
                    $key = $prefix.$args;
                    $result = Helper::isGood($options, $key) ? $options[$key] : null;
                }
            }
        } else {
            return $options;
        }

        return $result;

    }