Omnipay\Alipay\Requests\AbstractLegacyRequest::validateOne PHP Method

    protected function validateOne()
    {
        $keys = func_get_args();
        $allEmpty = true;
        foreach ($keys as $key) {
            $value = $this->parameters->get($key);
            if (!empty($value)) {
                $allEmpty = false;
                break;
            }
        }
        if ($allEmpty) {
            throw new InvalidRequestException(sprintf('The parameters (%s) must provide one at least', implode(',', $keys)));
        }
    }