Transpose proxy model from QtCentre example doesn't work, where is the error?

Question

PyQt

To solve the problem, you need a proxy model that transposes the table.
There is a ready example: Transpose proxy model .
I need to implement this on PyQt4 (more specifically PyQt 4.8, Python 2.7.8, Windows 7).
Here's what happened: source code and ui file .
My transposedView (lower right widget of the tableView class) does not show anything. The rest of the widgets work as they should.
It turned out that the createIndex method in TransposeModel always returns an invalid index.
What's wrong? Where to dig?