MainWindow.py

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("view/ui/MainWindow.ui", self)
        self.showMaximized()