code: def _prepare_directory(directory_path: str) -> str:
      
      exp_num = get_exp_dir_num(directory_path)
      exp_num = exp_num + 1
      exp_dir = os.path.join(directory_path, str(exp_num))
      if not os.path.isdir(exp_dir):
          os.makedirs(exp_dir)
      return exp_dir
docs: Prepare the directory structure required for the experiment
      :returns: returns the name of the newly created directory