PagSeguro and PagSeguroConfigWrapper

I'm working with PagSeguro in Laravel 5.3, the problem is the Class PagSeguroConfigWrapper that I need to generate to do the authentication, I do all the steps described in the documentation and it works only if I use the authentication after the instance of the class PagSeguroPaymentRequest. Home See the example:

It works

    new PagSeguroPaymentRequest();
    $credentials = PagSeguroConfig::getAccountCredentials();

    $transaction = PagSeguroTransactionSearchService::searchByCode($credentials, $transaction_code);

Does not work, error: Credentials not set

    $credentials = PagSeguroConfig::getAccountCredentials();

    $transaction = PagSeguroTransactionSearchService::searchByCode($credentials, $transaction_code);