Código de Python - Navegador web con PyQT5

#!/usr/bin/env python

# -*- coding: utf-8 -*-

#

#       Simple navegador web con PyQt 5.

#

#       Copyright 2018 Recursos Python - www.recursospython.com

#

#

import sys

from PyQt5.QtCore import QUrl

from PyQt5.QtWidgets import QApplication, QHBoxLayout, QLineEdit

from PyQt5.QtWidgets import QMainWindow, QPushButton, QVBoxLayout

from PyQt5.QtWidgets import QWidget

from PyQt5.QtWebEngineWidgets import QWebEngineView

class Widgets(QMainWindow):

    def __init__(self):

        QMainWindow.__init__(self)

        self.setWindowTitle("Simple Web Browser")

        self.widget = QWidget(self)

        # Widget para el navegador

        self.webview = QWebEngineView()

        self.webview.load(QUrl("https://www.google.com/"))

        self.webview.urlChanged.connect(self.url_changed)

        # Ir hacia atrás

        self.back_button = QPushButton("<")

        self.back_button.clicked.connect(self.webview.back)

        # Ir hacia adelante

        self.forward_button = QPushButton(">")

        self.forward_button.clicked.connect(self.webview.forward)

        # Actualizar la página

        self.refresh_button = QPushButton("Actualizar")

        self.refresh_button.clicked.connect(self.webview.reload)

        # Barra de direcciones

        self.url_text = QLineEdit()

        # Cargar la página actual

        self.go_button = QPushButton("Ir")

        self.go_button.clicked.connect(self.url_set)

        self.toplayout = QHBoxLayout()

        self.toplayout.addWidget(self.back_button)

        self.toplayout.addWidget(self.forward_button)

        self.toplayout.addWidget(self.refresh_button)

        self.toplayout.addWidget(self.url_text)

        self.toplayout.addWidget(self.go_button)

        self.layout = QVBoxLayout()

        self.layout.addLayout(self.toplayout)

        self.layout.addWidget(self.webview)

        self.widget.setLayout(self.layout)

        self.setCentralWidget(self.widget)

    def url_changed(self, url):

        """Actualizar la barra de direcciones"""

        self.url_text.setText(url.toString())

    def url_set(self):

        """Acceder a un nuevo URL"""

        self.webview.setUrl(QUrl(self.url_text.text()))

if __name__ == "__main__":

    app = QApplication(sys.argv)

    window = Widgets()

    window.show()

    sys.exit(app.exec_())