title: chr() equivalent returning a bytes object, in py3k
body: <p>Python 2.x has <code>chr()</code>, which converts a number in the range 0-255 to a byte string with one character with that numeric value, and <code>unichr()</code>, which converts a number in the range 0-0x10FFFF to a Unicode string with one character with that Unicode codepoint.  Python 3.x replaces <code>unichr()</code> with <code>chr()</code>, in keeping with its "Unicode strings are default" policy, but I can't find anything that does exactly what the old <code>chr()</code> did.  The <code>2to3</code> utility (from 2.6) leaves <code>chr</code> calls alone, which is not right in general :(</p>
  
  <p>(This is for parsing and serializing a file format which is explicitly defined in terms of 8-bit bytes.)</p>