import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.5
import QtQuick.Layouts 1.3
Window {
    width: 1280
    height: 720
    visible: true
    title: qsTr("Application attempt #51")
    color:"#88000000"
    SwipeView{
        id:mainSwipeView
        x:0
        y:0
        width:parent.width
        height:parent.height
        //Main Download Page
        Component.onCompleted: {
            if (pyModel.rowCount() === 0){
                currentIndex = 1;
            } else {
                currentIndex = 0;
            }
        }
        Rectangle {
            color:"#00000000"
            Rectangle{
                color:"#88000000"
                width:parent.width
                height:80
                x:0
                y:0
                Button{
                    x:0
                    y:0
                    height:parent.height
                    width:parent.width/3
                    background:Rectangle{
                        color:"#00000000"
                    }
                    onClicked:{mainSwipeView.currentIndex = 1;}
                    Label{
                        text: "Add"
                        anchors.centerIn: parent
                        font.pixelSize: 20
                        color:"white"
                    }
                }
                Button{
                    x:parent.width/3
                    y:0
                    height:parent.height
                    width:parent.width/3
                    Label{
                        text: "Remove"
                        anchors.centerIn: parent
                        font.pixelSize: 20
                        color:"white"
                    }
                    font.pixelSize: 20
                    background:Rectangle{
                        color:"#00000000"
                    }
                    onClicked:{pyModel.removeSelected();}
                }
                Button{
                    x:parent.width*2/3
                    font.pixelSize: 20
                    y:0
                    Label{
                        text: "Pause"
                        anchors.centerIn: parent
                        font.pixelSize: 20
                        color:"white"
                    }
                    height:parent.height
                    width:parent.width/3
                    background:Rectangle{
                        color:"#00000000"
                    }
                }
            }
            ListView{
                model:pyModel
                clip:true
                contentHeight: 100
                width:parent.width
                height:parent.height-80
                y:80
                x:0
                delegate: Rectangle{
                    Rectangle{
                        z:-1
                        color:"#aa000000"
                        height:parent.height
                        width:(model.percentage/100)*parent.width
                    }

                    color:"#44000000"
                    height:100
                    width:parent.width
                    CheckBox{
                        checked: model.isChecked
                        onClicked: model.isChecked = checked // I guess here is the error
                        x:0
                        y:0
                        width:100
                        height:100
                    }

                    Label{
                        text:model.name
                        x:110
                        y:10
                        color:"white"
                        font.pixelSize: 24
                    }
                    Label{
                        text:"Progress: "+String(model.percentage)+"%"
                        x:120
                        font.pixelSize: 17
                        y:(parent.height-20)-height/2
                        color:"white"
                    }
                    Label{
                        text:"Status: "+String(model.status)
                        x:parent.width-(width+20)
                        font.pixelSize: 17
                        y:(parent.height-20)-height/2
                        color:"white"
                    }
                }
            }
        }
        Rectangle {
            color:"#88000000"

            //TopBar
            Rectangle{
                color:"#88000000"
                width:parent.width
                height:80
                x:0
                y:0
                Button{
                    x:0
                    y:0
                    height:parent.height
                    width:parent.width/3
                    background:Rectangle{
                        color:"#00000000"
                    }
                    onClicked:{mainSwipeView.currentIndex = 0;}
                    Label{
                        text: "Show Queue"
                        anchors.centerIn: parent
                        font.pixelSize: 20
                        color:"white"
                    }
                }
            }
            //MainSection
            Item{
                y:80
                x:0
                width:parent.width
                height:parent.height-80
                Label{
                    text:"Hey, Welcome Again"
                    font.pixelSize: 72
                    color:"white"
                    x:parent.width/2-width/2
                    y:linkinputTextBox.y-(height/2+100)
                }

                TextField{
                    id:linkinputTextBox
                    placeholderText: "Video Link"
                    x:100
                    width:parent.width-410
                    font.pixelSize: 24
                    background: Rectangle{
                        color:"#88000000"
                    }
                    color: "white"
                    y:parent.height/2-height/2
                }
                Button{
                    width:200
                    height:linkinputTextBox.height
                    y:parent.height/2-height/2
                    x:parent.width-300
                    Label{
                        text:"Go"
                        color:"white"
                        font.pixelSize: 24
                        anchors.centerIn: parent
                    }
                    background: Rectangle{
                        color:"#88000000"
                    }
                }
            }
        }
    }
}

main.py

# This Python file uses the following encoding: utf-8
import sys
from pathlib import Path

from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine
from PySide2.QtCore import QAbstractListModel,QModelIndex,Qt,Slot

class Model(QAbstractListModel):

    _col1 = Qt.UserRole + 1
    _col2 = Qt.UserRole + 2
    _col3 = Qt.UserRole + 3
    _col4 = Qt.UserRole + 4
    _col5 = Qt.UserRole + 5
    def __init__(self, parent=None):
        super(Model, self).__init__(parent)

        # Each item is a dictionary of key/value pairs
        self.myData = []
    def append(self, item):
        """Append item to end of model"""
        self.beginInsertRows(QModelIndex(),
                             self.rowCount(),
                             self.rowCount())

        self.myData.append(item)
        self.endInsertRows()
    @Slot(int)
    def remove(self, index):
        self.beginRemoveRows(QModelIndex(),index,index)
        self.myData.pop(index)
        self.endRemoveRows()
    @Slot()
    def removeSelected(self):
        i=0
        while(i != self.rowCount()):
            if self.myData[i]["isChecked"]:
                self.remove(i)
            else:
                i+=1
    def data(self, index, role):
        """Return value of item[`index`] of `role`"""
        row = index.row()
        if index.isValid() and 0 <= row < self.rowCount():
            if role == self._col1:
                return self.myData[row]["name"]
            if role == self._col2:
                return self.myData[row]["status"]
            if role == self._col3:
                return self.myData[row]["percentage"]
            if role == self._col4:
                return self.myData[row]["isChecked"]
            if role == self._col5:
                return self.myData[row]["uid"]
    def setData(self, index, value, role):
        """Set item[`index`] of `role` to `value`"""
        self.myData[index.row()][role] = value
        self.dataChanged.emit(index, index)

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

    def roleNames(self):
        return {
    self._col1: b"name",
    self._col2: b"status",
    self._col3: b'percentage',
    self._col4: b'isChecked',
    self._col5: b'uid'}
model = Model()
model.append({"uid":0,"name":"an","status":"down","percentage":10,"isChecked":False})
model.append({"uid":1,"name":"an","status":"down","percentage":40,"isChecked":False})
model.append({"uid":2,"name":"an","status":"down","percentage":20,"isChecked":True})
model.append({"uid":3,"name":"an","status":"down","percentage":60,"isChecked":False})
model.append({"uid":4,"name":"an","status":"down","percentage":80,"isChecked":False})
model.append({"uid":5,"name":"an","status":"down","percentage":90,"isChecked":False})
model.append({"uid":6,"name":"an","status":"down","percentage":100,"isChecked":False})
model.append({"uid":7,"name":"an","status":"down","percentage":0,"isChecked":False})
if __name__ == "__main__":
    app = QGuiApplication(sys.argv)
    engine = QQmlApplicationEngine()
    engine.rootContext().setContextProperty("pyModel", model)
    qml_file = Path(__file__).resolve().parent / "main.qml"
    engine.load(str(qml_file))
    if not engine.rootObjects():
        sys.exit(-1)
    sys.exit(app.exec_())

I am getting some error like sys:1: RuntimeWarning: Invalid return value in function QAbstractListModel.setData, expected bool, got NoneType. when I check the checkbox. But checked is actually a bool but it says it's None type. I tried console.log(checked) it return bool but Idk why this error occur.

Thank you