def UnpackSortKeyPrefix(prefix):
 (timestamp, random_bits) = struct.unpack('>IH', base64hex.B64HexDecode(prefix))
 return timestamp

def UnpackSortKeyPrefix ( prefix ) : ( timestamp , random_bits ) = struct . unpack ( '>IH' , base64hex . B64HexDecode ( prefix ) ) return timestamp
returns the timestamp in the provided sort key prefix .