UI doesn't update when Python QAbstractListModel changes from a Thread

[qtpublicname]

I posted the following as a QT bug, but after further work I am beginning to think that I am missing something:

--
When running the attached code the UI doesn't update until i resize the window, and I get the following error:

QObject::connect: Cannot queue arguments of type 'QQmlChangeSet'
(Make sure 'QQmlChangeSet' is registered using qRegisterMetaType().)

I am not sure if this is PySide 2 bug, an underlying QT issue, or I am supposed to do something in my code to make this work.

Also I reported the issue as 5.12.2 of QT but it may be in 5.11.2, as I have both installed.

--
So I am now wondering if the issue is that i somehow have to update the QAbstractListModel from the UI thread and not from my own thread -- the equivalent of Platform.runLater in JavaFX. So how do I do that?

Also how do I actually change the ListView's model from Python? I don't want to change the contents of the ListView's model, I want to change it to a completely different model ....

thanks
G

-- here is the code -- can't upload it for some reason

-- python code

import sys
from PySide2.QtCore import QAbstractListModel, Qt, QByteArray, SIGNAL, QModelIndex
from PySide2.QtGui import QGuiApplication
from PySide2.QtWidgets import QListView
from PySide2.QtQuick import QQuickView
from PySide2.QtQml import QQmlComponent
from PySide2.QtQml import qmlRegisterType


class PersonModel (QAbstractListModel):
    MyRole = Qt.UserRole + 1

    def __init__(self, parent = None):
        QAbstractListModel.__init__(self, parent)
        self._data = []

    def roleNames(self):
        roles = {
            PersonModel.MyRole : QByteArray(b'modelData'),
            Qt.DisplayRole : QByteArray(b'display')
        }
        return roles

    def rowCount(self, parent=QModelIndex()):
        return len(self._data)

    def data(self, index, role):
        d = self._data[index.row()]

        if role == Qt.DisplayRole:
            return d['name']
        elif role == Qt.DecorationRole:
            return Qt.black
        elif role == PersonModel.MyRole:
            return d['myrole']
        return None


    def appendRow(self, n, t):
        self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
        self._data.append({'name':n, 'myrole':t})
        self.endInsertRows()

    def populate(self):
        self.appendRow('Asterix', 'role1')
        self.appendRow('Obelix', 'role2')

from threading import Thread
from time import sleep

def function01(arg, myModel, name):
    for i in range(arg):
        print(name,'i---->',i,'\n')
        print (name,"arg---->",arg,'\n')
        sleep(10)
        myModel.appendRow(name + str(i),  'role1')
        # index = len(myModel._data)
        # myModel.foo(index)

if __name__ == '__main__':
    app = QGuiApplication(sys.argv)

    # qmlRegisterType(PersonModel, 'Charts', 1, 0, 'PersonModel');
    # qmlRegisterType(PersonModel, 'Charts', 1, 0, 'PersonModel');

    view = QQuickView()

    view.setResizeMode(QQuickView.SizeRootObjectToView)

    myModel = PersonModel()
    myModel.populate()

    print(myModel._data)

    view.rootContext().setContextProperty("myModel", myModel)
    view.setSource('view.qml')

    thread1 = Thread(target=function01, args=(5, myModel, 'thread1',))
    thread1.start()
    # thread1.join()
    # thread2.join()

    view.show()
    app.exec_()
    # Deleting the view before it goes out of scope is required to make sure all child QML instances
    # are destroyed in the correct order.
    del view

-- view.qml
import QtQuick 2.0


ListView {
    id : xxx
    width: 100
    height: 100
    anchors.fill: parent
    model: myModel
    delegate: Component {
        Rectangle {
            height: 25
            width: 100
            Text {
                function displayText() {
                    var result = ""
                    if (typeof display !== "undefined")
                        result = display + ": "
                    result += modelData
                    return result
                }

                text: displayText()
            }
        }
    }
}