text: import os
  import json
  
  def prepare_custom_db(f, im_folder, data_split):
      model_list = [o for o in os.listdir(im_folder)
                    if os.path.isdir(os.path.join(im_folder,o))]
      with open(f, 'w') as out:
          json.dump({im_folder: {
              "name":"cars",
              data_split: model_list}}, out)
  
  