def METHOD_NAME (data_dirs,data_subset):
  print("Step 1.  Get a list of all files")
  file_names = []
  for dir_name in data_dirs :
    if not os.path.isdir(dir_name):
      continue
    for file_name in os.listdir(dir_name):
      if eval_ending(file_name) is not None: # only accept jsons
        if data_subset == 0 or \
          (data_subset == 1 and int(eval_ending(file_name)[0][-1]) % 2 == 1 or \
          (data_subset == 2 and int(eval_ending(file_name)[0][-1]) % 2 == 0)):
          file_names.append(os.path.join(dir_name, file_name))
  print("Number of frames found:", len(file_names))
  return file_names