code: def no_counterpart_found(string, options, rc_so_far):
      
      logger.debug("options.else_action: %s", options.else_action)
      if options.else_action == "passthrough":
          format_list = [string]
          output_fd = sys.stdout
      elif options.else_action == "exception":
          raise KeyError("No counterpart found for: %s" % (string))
      elif options.else_action == "error":
          format_list = ["# No counterpart found for: %s" % (string)]
          output_fd = sys.stderr
      if not options.no_newline:
          format_list.append("\n")
      output_fd.write("".join(format_list))
      return options.else_errno
docs: Takes action determined by options.else_action.  Unless told to
      raise an exception, this function returns the errno that is supposed
      to be returned in this case.
  
      :param string: The lookup string.
      :param options: ArgumentParser or equivalent to provide
          options.else_action, options.else_errno, options.no_newline
      :param rc_so_far: Becomes set to the value set in options.