When using perspectiveTransform in rather complicated settings, it would be easier for developers to have two separate assertions for each part of the boolean expression in order to pinpoint problems more efficiently. In my case I am struggling in Python2.7 with finding out whether scn+1 == m.cols or the depth == CV_32F || depth == CV_64F is making a problem, which is kind of hard.

The keys() and values() functions on dictionaries in Python 3 no longer
return lists.  pyopencv_to() for flann::IndexParams now iterates over
the dictionary in a way that is version-agnostic.