yii\httpclient\Request::composeFormInputs PHP Метод

    private function composeFormInputs(array $data, $baseKey = '')
    {
        $result = [];
        foreach ($data as $key => $value) {
            if (!empty($baseKey)) {
                $key = $baseKey . '[' . $key . ']';
            }
            if (is_array($value)) {
                $result = array_merge($result, $this->composeFormInputs($value, $key));
            } else {
                $result[$key] = $value;
            }
        }
        return $result;
    }