4.7.1. ISO-10646 escapes

The \u and \U are 16 and 32 bit escapes for ISO-10646 code points, requiring exactly 4 or 8 hexadecimal digits. The expansion of these escapes in an 8 bit string is the UTF-8 encoding of the corresponding code point. Note that '\xF0' and '\u00F0' are NOT the same strings! The former consists of a single byte, value 0xF0, the latter is a two byte UTF-8 sequence for the Latin-1 character with code point 0xF0 (ETH), which is the two byte string '\xC3\xB0'.