code: def delim(arguments):
      
  
      if bool(arguments.control_files) == bool(arguments.directory):
          raise ValueError(
                  'Exactly one of control_files and `-d` must be specified.')
  
      if arguments.directory:
          arguments.control_files.extend(control_iter(arguments.directory))
  
      with arguments.output as fp:
          results = _delim_accum(arguments.control_files,
                  arguments.file_template, arguments.keys,
                  arguments.exclude_keys, arguments.separator,
                  missing_action=arguments.missing_action)
          r = next(results)
          writer = csv.DictWriter(fp, r.keys(), delimiter=arguments.separator)
          writer.writeheader()
          writer.writerow(r)
          writer.writerows(results)
docs: Execute delim action.
  
      :param arguments: Parsed command line arguments from :func:`main`