code: def prompt_file(prompt, default=None, must_exist=True, is_dir=False, 
                  show_default=True, prompt_suffix=': ', color=None):
      
  
      if must_exist:
          while True:
              r = prompt_autocomplete(prompt, path_complete(is_dir), default, show_default=show_default,
                                      prompt_suffix=prompt_suffix, color=color)
              if os.path.exists(r):
                  break
              print('This path does not exist.')
      else:
          r = prompt_autocomplete(prompt, path_complete(is_dir), default, show_default=show_default,
                                  prompt_suffix=prompt_suffix, color=color)
  
      return r
docs: Prompt a filename using using glob for autocompetion.
  
      If must_exist is True (default) then you can be sure that the value returned
      is an existing filename or directory name.
      If is_dir is True, this will show only the directories for the completion.