How to build a Simple Browser in Python

import sys
from PyQt5.QtCore import QUrl, Qt
from PyQt5.QtWidgets import QApplication, QMainWindow, QStatusBar, QToolBar, QAction, QLineEdit, QVBoxLayout, QWidget
from PyQt5.QtWebEngineWidgets import QWebEngineView, QWebEngineSettings
from PyQt5.QtCore import QThread, pyqtSignal
import time

class Browser(QMainWindow):
    def __init__(self):
        super().__init__()

        self.browser = QWebEngineView()
        self.browser.setUrl(QUrl("http://www.google.com"))

        self.setCentralWidget(self.browser)

        self.status = QStatusBar()
        self.setStatusBar(self.status)

        navtb = QToolBar("Navigation")
        self.addToolBar(navtb)

        back_btn = QAction("Back", self)
        back_btn.setStatusTip("Back to previous page")
        back_btn.triggered.connect(self.browser.back)
        navtb.addAction(back_btn)

        next_btn = QAction("Forward", self)
        next_btn.setStatusTip("Forward to next page")
        next_btn.triggered.connect(self.browser.forward)
        navtb.addAction(next_btn)

        reload_btn = QAction("Reload", self)
        reload_btn.setStatusTip("Reload page")
        reload_btn.triggered.connect(self.browser.reload)
        navtb.addAction(reload_btn)

        home_btn = QAction("Home", self)
        home_btn.setStatusTip("Go home")
        home_btn.triggered.connect(self.navigate_home)
        navtb.addAction(home_btn)

        navtb.addSeparator()

        self.urlbar = QLineEdit()
        self.urlbar.returnPressed.connect(self.navigate_to_url)
        navtb.addWidget(self.urlbar)

        stop_btn = QAction("Stop", self)
        stop_btn.setStatusTip("Stop loading current page")
        stop_btn.triggered.connect(self.browser.stop)
        navtb.addAction(stop_btn)

        layout = QVBoxLayout()
        layout.addWidget(navtb)
        layout.addWidget(self.browser)

        container = QWidget()
        container.setLayout(layout)
        self.setCentralWidget(container)

        self.showMaximized()

    def navigate_home(self):
        self.browser.setUrl(QUrl("http://www.google.com"))

    def navigate_to_url(self):
        q = QUrl(self.urlbar.text())
        if q.scheme() == "":
            q.setScheme("http")

        self.browser.setUrl(q)

    def update_title(self):
        title = self.browser.page().title()
        self.setWindowTitle("% s - Enhanced Browser" % title)

    def showEvent(self, event):
        super().showEvent(event)
        # Set up QWebEngineSettings for optimizations
        settings = self.browser.settings()
        settings.setAttribute(QWebEngineSettings.LocalStorageEnabled, True)
        settings.setAttribute(QWebEngineSettings.PluginsEnabled, True)
        settings.setAttribute(QWebEngineSettings.JavascriptEnabled, True)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    QApplication.setApplicationName("Enhanced Browser")
    window = Browser()
    app.exec_()