code: def all_files_exist(file_list):
      
      all_exist = True
      for filename in file_list:
          all_exist = all_exist and os.path.isfile(filename)
      return all_exist
docs: Check if all files exist.
  
      :param file_list: the names of files to check.
  
      :type file_list: list
  
      :returns: ``True`` if all files exist, ``False`` otherwise.