pyqt/designer/example_2.py

import os.path
import sys

from PyQt5 import uic
from PyQt5.QtWidgets import QApplication, QMainWindow
from MainWindow import Ui_MainWindow

basedir = os.path.dirname(__file__)


class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self):
        super().__init__()
        self.setupUi(self)


app = QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec_()