pyqtProperty(dict) fails in PyQt 5.10 with TypeError but works in 5.8.2

main.py

import sys
from PyQt5.QtCore import QObject, pyqtProperty, pyqtSignal
from PyQt5.QtWidgets import QApplication
from PyQt5.QtQml import QQmlApplicationEngine, qmlRegisterType


class Interface(QObject):
    def __init__(self, parent=None):
        super().__init__(parent=parent)

    mydictChanged = pyqtSignal()

    @pyqtProperty(dict, notify=mydictChanged)
    def mydict(self):
        dct = {"a": 1, "b": 2}
        return dct


qmlRegisterType(Interface, 'org.MyInterface', 1, 0, 'MyInterface')

QML = b"""
import QtQuick 2.0
import QtQuick.Controls 1.4
import org.MyInterface 1.0

ApplicationWindow {
    width: 300
    height: 300
    visible: true

    property MyInterface iface : MyInterface {}

    Column {
        Text {
            text : iface.mydict.a
        }
        Text {
            text : iface.mydict.b
        }
    }
 }
"""

if __name__ == "__main__":
    app = QApplication(sys.argv)
    engine = QQmlApplicationEngine()
    engine.loadData(QML)
    sys.exit(app.exec_())

output

$ pip freeze | grep PyQt5
PyQt5==5.9
$ python main.py
TypeError: unable to convert a Python 'dict' object to a C++ 'PyQt_PyObject' instance
fish: “python main.py” terminated by signal SIGABRT (Abort)

The is incorrect. https://www.riverbankcomputing.com/pipermail/pyqt/2018-February/040010.html