Braintree\MerchantGateway::_verifyGatewayResponse PHP Method

    private function _verifyGatewayResponse($response)
    {
        if (isset($response['response']['merchant'])) {
            // return a populated instance of merchant
            return new Result\Successful([Merchant::factory($response['response']['merchant']), OAuthCredentials::factory($response['response']['credentials'])]);
        } else {
            if (isset($response['apiErrorResponse'])) {
                return new Result\Error($response['apiErrorResponse']);
            } else {
                throw new Exception\Unexpected("Expected merchant or apiErrorResponse");
            }
        }
    }