code: public OperationStatus deleteUnlabelledUtterance(UUID appId, String versionId, String utterance) {
          return deleteUnlabelledUtteranceWithServiceResponseAsync(appId, versionId, utterance).toBlocking().single().body();
      }
docs: Deleted an unlabelled utterance.
  
  @param appId The application ID.
  @param versionId The version ID.
  @param utterance The utterance text to delete.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws ErrorResponseException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the OperationStatus object if successful.