Trying some pyqt5 source from somewhere...

import sys
import webview
from flask import Flask, render_template
from PyQt5.QtCore import QSize, Qt
from PyQt5.QtGui import *
from PyQt5.QtWebKit import *
from PyQt5.QtWidgets import *
from PyQt5.QtWebKitWidgets import QWebView

class WebWidget(QWidget):

    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        painter.setBrush(Qt.white)
        painter.setPen(Qt.black)
        painter.drawRect(self.rect().adjusted(0, 0, -1, -1))
        painter.setBrush(Qt.red)
        painter.setPen(Qt.NoPen)
        painter.drawRect(self.width()/4, self.height()/4,
                         self.width()/2, self.height()/2)
        painter.end()

    def sizeHint(self):
        return QSize(100, 100)

class WebPluginFactory(QWebPluginFactory):

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

    def create(self, mimeType, url, names, values):
        if mimeType == "x-pyqt/widget":
            return WebWidget()

    def plugins(self):
        plugin = QWebPluginFactory.Plugin()
        plugin.name = "PyQt Widget"
        plugin.description = "An example Web plugin written with PyQt."
        mimeType = QWebPluginFactory.MimeType()
        mimeType.name = "x-pyqt/widget"
        mimeType.description = "PyQt widget"
        mimeType.fileExtensions = []
        plugin.mimeTypes = [mimeType]
        print("plugins")
        return [plugin]

if __name__ == "__main__":

    app = QApplication(sys.argv)
    QWebSettings.globalSettings().setAttribute(QWebSettings.PluginsEnabled, True)
    server = Flask(__name__, template_folder='templates') # comment out if necessary
    view = webview.create_window('Hello to All!','templates/Mike.html') # comment out if necessary
    view = QWebView()
    factory = WebPluginFactory()
    view.page().setPluginFactory(factory)
    view.setHtml()
    view.show()
    sys.exit(app.exec_())
    webview.start()