I use Qt for Python and subclassed QAbstractItemModel to create a model for my treeView. For the data structure I used nodes. Each node has a parent and a childList to represent the data structure.

When I call the createIndex method I passed as the third argument the node itself, which worked fine. After upgrading from Qt for Python 5.11.2 to 5.12 it gives an error, that it expects other input parameter. Here is the error:
 TypeError: 'PySide2.QtCore.QAbstractItemModel.createIndex' called with wrong argument types:
PySide2.QtCore.QAbstractItemModel.createIndex(int, int, Node)
Supported signatures:
PySide2.QtCore.QAbstractItemModel.createIndex(int, int, quintptr = 0)
PySide2.QtCore.QAbstractItemModel.createIndex(int, int, void = nullptr)

Regards
Daniel