Instead of implementing all the intricacies of a cmp for the python
sort-function, support for which is due to be dropped at Python 3 in
any case, implement a much simpler key function that achieves the same
result.
In the process, eliminate the ugly kludge of setting an attribute on a
function to, in effect, communicate with it via a global. Instead,
instantiate a class, that wraps the value previously given to the
attribute and whose instance provides the key-function.
Thanks to Ievgenii Meshcheriakov <ievgenii.meshcheriakov@qt.io> for
pointing out that a key function is the way of the future - and
sorted() is a nicer way to sort.
Pick-to: 6.2
Change-Id: Icf1ed5597fedf420d054fbc860e3e7fc6615875c
Reviewed-by: Ievgenii Meshcheriakov <ievgenii.meshcheriakov@qt.io>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>