docs: def _UInt(s):
    """Converts string to Unicode code point ('263A' => 0x263a).
  
    Args:
      s: string to convert
  
    Returns:
      Unicode code point
  
    Raises:
      InputError: the string is not a valid Unicode value.
    """
  
    try:
      v = int(s, 16)
    except ValueError:
      v = -1
    if len(s) < 4 or len(s) > 6 or v < 0 or v > _RUNE_MAX:
      raise InputError("invalid Unicode value %s" % (s,))
    return v