public function signatureParameters(array $protocolParameters, array $requestOptions = [])
    {
        $parameters = $protocolParameters;

        if ($this->requestOptionsHas($requestOptions, 'query')) {
            $parameters = array_merge($parameters, $requestOptions['query']);
        }

        if ($this->requestOptionsHas($requestOptions, 'form_params')) {
            $parameters = array_merge($parameters, $requestOptions['form_params']);
        }

        return $parameters;
    }