def groups_option(f):
    new_func = click.option("-g", "--groups",
                            help="Comma-separated list of requirement groups "
                            "to include.")(f)
    return update_wrapper(new_func, f)
def _scale_vars(s, v_list):
  """Scale all variables in v_list by s."""
  return [s * v for v in v_list]