code: private File getFileFromConfigDirectory(String file, File def) {
          File f = new File(configDirectory, file);
          if (configDirectory != null && f.exists()) {
              return f;
          }
          if (def != null && def.exists()) {
              return def;
          }
          return null;
      }
docs: /*
  Get the file from configDrectory if it exists;
  otherwise return def only if it exists, or null if not