Qestions using futurize and QtCore.Signal

[smaraux]

Here is a feedback about the issue : after investigation, Katana uses PyQt5 while others use PySide2. This makes a difference in signal declaration, as PyQt5 is incompatible with future 'object' type. To make all this world work OK in python 2 & 3, I had to declare a "signalObject" which has a different value if using pyqt('PyQt_PyObject') or pyside ('PyObject') and use it as signal declaration argument.