public function removeDuplicates($values)
    {
        foreach ($values as $key => $option) {
            $value = $this->getCmsPageValue($option);
            if ($value) {
                if ($this->listHasValue($value)) {
                    unset($values[$key]);
                } else {
                    $this->setListValue($value);
                }
            }
        }

        return $values;
    }