docs: def _URange(s):
    """Converts string to Unicode range.
  
      '0001..0003' => [1, 2, 3].
      '0001' => [1].
  
    Args:
      s: string to convert
  
    Returns:
      Unicode range
  
    Raises:
      InputError: the string is not a valid Unicode range.
    """
    a = s.split("..")
    if len(a) == 1:
      return [_UInt(a[0])]
    if len(a) == 2:
      lo = _UInt(a[0])
      hi = _UInt(a[1])
      if lo < hi:
        return range(lo, hi + 1)
    raise InputError("invalid Unicode range %s" % (s,))