protected function sanitizeValueFor($key, $value)
    {
        foreach ($this->rules[$key] as $rule) {
            $value = call_user_func_array(
                $this->getCallable($rule[0], $key),
                $this->buildArguments($value, isset($rule[1]) ? $rule[1] : null)
            );
        }

        return $value;
    }