Six is called the &quot;Python 2 and 3 Compatibility Library&quot; for a reason. I&#x27;m certain that when Python 4 will be released six will be updated so that six.PY3 will include Python 4.<p>Of course, this opens the opportunity for two other compatibility libraries. &quot;twelve&quot; will be for supporting Python 3 and 4 and &quot;twentyfour&quot; will support Python 2, 3, and 4 at once (I hope nobody will seriously consider a library called &quot;eight&quot;).