MainWindow.py

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

import os

from PyQt5 import QtGui
from PyQt5.QtWidgets import (
    QMainWindow, QApplication,
)
from PyQt5.uic import loadUi

class ApplicationWindow(QMainWindow):
    def __init__(self):
        super(ApplicationWindow, self).__init__()
        self.ui = loadUi(
            os.path.join(os.path.dirname(__file__), "ui", "MainWindow.ui"),
            self
        )
        self.showMaximized()