Class for Each QStackedWidget Page

I am using PyQt5 and Qt-Designer to design an application.

How do I instantiate a class for each page on QstackedWidget. I can do it in a single class, all widgets belong to the same QMainWindow. But, the issue is that the file will get too long and impracticale. How do I assign a class for each page. For example, class I handles all the widgets on Page I and class II handles all the widgets on Page II; in the QMainWindow file I can just assign an Object that represents each page.

How can I do it?

Just create multiple modules:

widget1.py

from PyQt5.QtWidgets import QWidget
class Widget1(QWidget):
    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)

widget2.py

from PyQt5.QtWidgets import QWidget
class Widget2(QWidget):
    def __init__(self, *args, **kwargs):
        QWidget.__init__(self, *args, **kwargs)

main.py

from widget1 import Widget1
from widget2 import Widget2
from PyQt5.QtWidgets import QMainWindow, QApplication

class MainWindow(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.setTitle("Stackked widget demo")
        self.stacked = QStackedWidget(self)
        self.setCentralWidget(self.stacked)
        self.widget1 = Widget1()
        self.stacked.addWidget(self.widget1)
        self.widget2 = Widget2()
        self.stacked.addWidget(self.widget2)

if __name__ == "__main__":
    app = QApplication([])
    mainwin = MainWindow()
    mainwin.show()
    app.exec_()