code: def join_options(options):
      
      rv = []
      any_prefix_is_slash = False
      for opt in options:
          prefix = split_opt(opt)[0]
          if prefix == '/':
              any_prefix_is_slash = True
          rv.append((len(prefix), opt))
  
      rv.sort(key=lambda x: x[0])
  
      rv = ', '.join(x[1] for x in rv)
      return rv, any_prefix_is_slash
docs: Given a list of option strings this joins them in the most appropriate
      way and returns them in the form ``(formatted_string,
      any_prefix_is_slash)`` where the second item in the tuple is a flag that
      indicates if any of the option prefixes was a slash.