PyQt & QML object ownership problem

pyqt_qml_ownership_problem.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os
import sys
import signal
from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQuick import QQuickView
from PyQt5.QtCore import QUrl, QObject, QVariant, pyqtSlot
from PyQt5.QtQml import QQmlEngine, qmlRegisterType


class Dummy(QObject):

    def __del__(self):
        print("Deleted")


class GUIEntryPoint(QObject):

    @pyqtSlot(result=QVariant)
    def get_foo(self):
        foo = Dummy()
        print("Created {}".format(foo))
        print("Ownership after instantiation: {}".format(QQmlEngine.objectOwnership(foo)))
        #QQmlEngine.setObjectOwnership(foo, 1)  # has no effect
        return foo

    @pyqtSlot(QVariant)
    def print_foo(self, foo):
        print("{}, ownership: {}".format(foo, QQmlEngine.objectOwnership(foo)))


def run():
    signal.signal(signal.SIGINT, signal.SIG_DFL)

    app = QGuiApplication(sys.argv)

    # these don't seem to make a difference
    qmlRegisterType(GUIEntryPoint, 'GUIEntryPoint', 1, 0, 'GUIEntryPoint')
    qmlRegisterType(Dummy, 'Dummy', 1, 0, 'Dummy')

    qml_url = QUrl.fromLocalFile(os.path.join('zzz.qml'))
    view = QQuickView()

    gep = GUIEntryPoint()
    view.rootContext().setContextProperty('BE', gep)
    view.setSource(qml_url)

    view.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    run()

zzz.qml

import QtQuick 2.2


Rectangle {
    id: rootItem
    width: 640
    height: 400

    property var pleaseKeepMe: BE.get_foo()

    Component.onCompleted: {
        console.log("Completed");

        BE.print_foo(pleaseKeepMe);  // prints None, it has been deleted

        console.log("creating another");
        var x = BE.get_foo();
        // at this point x has already been deleted on the Python side
        console.log("created another");
        BE.print_foo(x);  // prints None

        console.log("\n\nPress CTRL-C to exit");
    }
}