code: def remove_unused_directories(src_folder, categories):
    
    files = os.listdir(src_folder)
    os.mkdir("unused")
    for name in files:
      full_path = os.path.join(src_folder, name)
      if os.path.isdir(full_path):
        if not( name in categories or name == "_background_noise_"):
          newPath = os.path.join("unused", name)
          print("moving: ", full_path, "-->", newPath)
          shutil.move(full_path, newPath)
docs: list all directories.
    Remove all that are not in categories list (excluding background noise)
    :param src_folder:
    :param categories:
    :return: