code: def do_fish_complete(cli, prog_name):
      
      commandline = os.environ['COMMANDLINE']
      args = split_args(commandline)[1:]
      if args and not commandline.endswith(' '):
          incomplete = args[-1]
          args = args[:-1]
      else:
          incomplete = ''
  
      for item, help in get_choices(cli, prog_name, args, incomplete):
          if help:
              echo("%s\t%s" % (item, re.sub('\s', ' ', help)))
          else:
              echo(item)
  
      return True
docs: Do the fish completion
  
      Parameters
      ----------
      cli : click.Command
          The main click Command of the program
      prog_name : str
          The program name on the command line
  
      Returns
      -------
      bool
          True if the completion was successful, False otherwise