code: def add_cli_write_bel_namespace(main: click.Group) -> click.Group:  # noqa: D202
      
  
      @main.command()
      @click.option('-d', '--directory', type=click.Path(file_okay=False, dir_okay=True), default=os.getcwd(),
                    help='output directory')
      @click.pass_obj
      def write(manager: BELNamespaceManagerMixin, directory: str):
          """Write a BEL namespace names/identifiers to terminology store."""
          manager.write_directory(directory)
  
      return main
docs: Add a ``write_bel_namespace`` command to main :mod:`click` function.