docs: def ok(no_exit, func, *args, **kwargs):
      """Exit if `ret` is not OK (a negative number)."""
      ret = func(*args, **kwargs)
      if no_exit or ret >= 0:
          return ret
      reason = errmsg[abs(ret)]
      error('{0}() returned {1} ({2})'.format(func.__name__, ret, reason))