如何从PyQt的QWebEnginePage.runJavaScript()中获取返回值

import sys
from PyQt5.QtCore import QUrl, QObject, pyqtSignal
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWebEngineWidgets import QWebEngineView, QWebEnginePage

class MyWebEnginePage(QWebEnginePage):
    # 定义一个信号，用于传递 JavaScript 返回值
    javaScriptResult = pyqtSignal(object)

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

    def runJavaScript(self, script, callback=None):
        # 重写 runJavaScript 方法
        super().runJavaScript(script, self._handleJavaScriptResult)

    def _handleJavaScriptResult(self, result):
        # 当 JavaScript 执行完毕时，发射信号
        self.javaScriptResult.emit(result)

class MyApp(QObject):
    def __init__(self):
        super().__init__()

        self.app = QApplication(sys.argv)
        self.web_view = QWebEngineView()
        self.web_page = MyWebEnginePage(self.web_view)

        # 连接信号和槽
        self.web_page.javaScriptResult.connect(self.onJavaScriptResult)

        self.web_view.setPage(self.web_page)
        self.web_view.load(QUrl("https://www.example.com"))

        sys.exit(self.app.exec_())

    def onJavaScriptResult(self, result):
        # 处理 JavaScript 返回值
        print("JavaScript 返回值:", result)

if __name__ == "__main__":
    MyApp()

pip install PyQt5 PyQtWebEngine