code: public boolean confirmInstalled(String packageName, List<String> output){
          if (output != null) {
              return output.stream().anyMatch(s -> s != null && s.contains(getInstallSuccess()));
          } else {
              return true; //may be successful
          }
      }
docs: Checks the output to confirm the package is installed.
  
  @param packageName package name, eg gpsd
  @param output result of the installation process
  @return returns true if the package is installed, false otherwise.