docs: def init_argparser_source_registry(
              self, argparser, default=None, help=(
                  'comma separated list of registries to use for gathering '
                  'JavaScript sources from the given Python packages'
              )):
          """
          For setting up the source registry flag.
          """
  
          argparser.add_argument(
              '--source-registry', default=default,
              dest=CALMJS_MODULE_REGISTRY_NAMES, action=StoreDelimitedList,
              metavar='<registry>[,<registry>[...]]',
              help=help,
          )
  
          argparser.add_argument(
              '--source-registries', default=default,
              dest=CALMJS_MODULE_REGISTRY_NAMES, action=StoreDelimitedList,
              help=SUPPRESS,
          )