The UI file error when I export .ui.qml to .py file

I see the answer that show the process to convert a .ui.qml file from Qt Design Studio to a .py file involves several steps(text) But I get misstake in the step of save the .qml file as .ui in Qt Creator. the mistake is “An error occurred when reading a UI file with one row and one column: Marking needs to start” ps: Qt Creator 15.0.1 Based on Qt 6.8.1 (MSVC 2022, x86_64)

Built on Jan 22 2025 13:47:55

From revision 0855a2e14d

Qt Design Studio 4.7 (4.7.0) Based on Qt 6.8.2 (MSVC 2022, x86_64)

Built on Feb 15 2025 13:18:04

From revision bfb74e5d04

Convert a .ui.qml file from Qt Design Studio to a .py file involves several steps: Step1. Export from Qt Design Studio: Save the file as a .qml file within Qt Design Studio. So I've been using Qt Design Studio to design a simple GUI(the project name is UIDesign). This is the Screen01.ui.qml

/*
This is a UI file (.ui.qml) that is intended to be edited in Qt Design Studio only.
It is supposed to be strictly declarative and only uses a subset of QML. If you edit
this file manually, you might introduce QML code that is not supported by Qt Design Studio.
Check out https://doc.qt.io/qtcreator/creator-quick-ui-forms.html for details on .ui.qml files.
*/

import QtQuick
import QtQuick.Controls
import UIDesign

Rectangle {
    id: rectangle
    width: Constants.width
    height: Constants.height

    color: Constants.backgroundColor

    Button {
        id: button
        text: qsTr("Press me")
        anchors.verticalCenter: parent.verticalCenter
        checkable: true
        anchors.horizontalCenter: parent.horizontalCenter

        Connections {
            target: button
            onClicked: animation.start()
        }
    }

    Text {
        id: label
        text: qsTr("Hello UIDesign")
        anchors.top: button.bottom
        font.family: Constants.font.family
        anchors.topMargin: 45
        anchors.horizontalCenter: parent.horizontalCenter

        SequentialAnimation {
            id: animation

            ColorAnimation {
                id: colorAnimation1
                target: rectangle
                property: "color"
                to: "#2294c6"
                from: Constants.backgroundColor
            }

            ColorAnimation {
                id: colorAnimation2
                target: rectangle
                property: "color"
                to: Constants.backgroundColor
                from: "#2294c6"
            }
        }
    }
    states: [
        State {
            name: "clicked"
            when: button.checked

            PropertyChanges {
                target: label
                text: qsTr("Button Checked")
            }
        }
    ]
}

I've saving the Screen01.ui.qml as Screen01.qml

**Step2:**Open in Qt Creator: Open the .qml file in Qt Creator. when I open the Screen01.qml in Qt Creator I found this message in the line "import UIDesign"

QML module not found (UlDesign).
Import paths:D:/0T/Tools/QtCreator/bin/qm
For qmake projects, use the QML lMPORT PATH variable to add import paths.For Qbs projects, declare and set a qmllmportPaths property in your product to add import paths.For qmlproject projects, use the importPaths property to add import paths.For CMake projects, make sure QML IMPORT PATH variable is in CMakeCache.txt.For qmlRegister. calls, make sure that you define the Module URl as a string literal

I'm a new user of Qt. I think the UIDesign module is not important and useful in the several steps. So I del this line to ignore this message.

Step3: Save as .ui: Save the file again, this time using the .ui extension. This step is crucial as the .ui.qml format from Qt Design Studio is not directly compatible with the tools used to generate Python code.

when I try to save the Screen01.qml as Screen01.ui file. This mistake occurred：

An error occurred when reading a UI file with 1 row and 1 column: Marking needs to start

I can not understand what error in the 1 row and 1 column. This the Screen01.ui file.

/*
This is a UI file (.ui.qml) that is intended to be edited in Qt Design Studio only.
It is supposed to be strictly declarative and only uses a subset of QML. If you edit
this file manually, you might introduce QML code that is not supported by Qt Design Studio.
Check out https://doc.qt.io/qtcreator/creator-quick-ui-forms.html for details on .ui.qml files.
*/

import QtQuick
import QtQuick.Controls

Rectangle {
    id: rectangle
    width: Constants.width
    height: Constants.height

    color: Constants.backgroundColor

    Button {
        id: button
        text: qsTr("Press me")
        anchors.verticalCenter: parent.verticalCenter
        checkable: true
        anchors.horizontalCenter: parent.horizontalCenter

        Connections {
            target: button
            onClicked: animation.start()
        }
    }

    Text {
        id: label
        text: qsTr("Hello UIDesign")
        anchors.top: button.bottom
        font.family: Constants.font.family
        anchors.topMargin: 45
        anchors.horizontalCenter: parent.horizontalCenter

        SequentialAnimation {
            id: animation

            ColorAnimation {
                id: colorAnimation1
                target: rectangle
                property: "color"
                to: "#2294c6"
                from: Constants.backgroundColor
            }

            ColorAnimation {
                id: colorAnimation2
                target: rectangle
                property: "color"
                to: Constants.backgroundColor
                from: "#2294c6"
            }
        }
    }
    states: [
        State {
            name: "clicked"
            when: button.checked

            PropertyChanges {
                target: label
                text: qsTr("Button Checked")
            }
        }
    ]
}

**Step4:**Convert to .py: Use the pyuic tool, which is part of PyQt or PySide, to convert the .ui file to a .py file. The command-line syntax is as follows:

pyuic5 -o output_file.py input_file.ui

I think the Screen01.ui is not correct. Because, in this step, the same mistake occurred：

An error occurred when reading a UI file with 1 row and 1 column: Marking needs to start