code: public PagedList<Certificate> listCertificates(DetailLevel detailLevel) throws BatchErrorException, IOException {
          return listCertificates(detailLevel, null);
      }
docs: Lists the {@link Certificate certificates} in the Batch account.
  
  @param detailLevel A {@link DetailLevel} used for filtering the list and for controlling which properties are retrieved from the service.
  @return A list of {@link Certificate} objects.
  @throws BatchErrorException Exception thrown when an error response is received from the Batch service.
  @throws IOException Exception thrown when there is an error in serialization/deserialization of data sent to/received from the Batch service.