from PyQt5.QtWidgets import QMainWindow, QApplication

from firstWindow import Ui_MainWindow
import sys

class MainWindow(QMainWindow,Ui_MainWindow):
    def __init__(self,parent=None):
        super(MainWindow,self).__init__(parent)
        self.setupUi(self)
        self.btn1.clicked.connect(self.btn1Clicked)
    def btn1Clicked(self):
        import selenium.webdriver



if __name__ == '__main__':
    app=QApplication(sys.argv)
    mainwindow=MainWindow()
    mainwindow.show()
    sys.exit(app.exec())