docs: public static File createFolder(String path, String dest_dir)
              throws BeastException {
          File f = new File(dest_dir);
          if (!f.isDirectory()) {
              try {
                  f.mkdirs();
              } catch (Exception e) {
                  logger.severe("Problem creating directory: " + path
                          + File.separator + dest_dir);
              }
          }
  
          String folderPath = createFolderPath(path);
  
          f = new File(f, folderPath);
          if (!f.isDirectory()) {
              try {
                  f.mkdirs();
              } catch (Exception e) {
                  String message = "Problem creating directory: " + path
                          + File.separator + dest_dir;
                  logger.severe(message);
                  throw new BeastException(message, e);
              }
          }
  
          return f;
      }