How to open a window on QPushButton click in PyQT5?

Question

linux

In the process of studying PyQT5, a lot of questions arose for which I can not find a clear answer.
I created the main form of the program in QT Designer, saved it as main.ui > ran through pyuic5 > got ui.py.
I created a second file so that when editing the ui form , my code would not fly into ui.py, so to launch the main form and work with it, I made the second main.py file:

from PyQt5 import QtCore, QtGui, QtWidgets
import sys
from os import system as go
from os import getcwd as mainpath
from ui import Ui_MainWindow //здесь импотированна форма ui.py полученная через PyUIC5

app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()

main_path =   "'{}'".format(str(mainpath())) # здесь я получаю путь к текущему файлу(запущеному)
path = "cd " + main_path + "/ui/  " # переход к папке /ui

def formstart():
  go( path + "&& python3 add-account.py") # Запуск /ui/add-account.py через os.system

ui.pushButton.clicked.connect( formstart ) # при нажатии кнопки запускается другая форма

sys.exit(app.exec_())

This method does not suit me at all, with this method the main form completely stops responding until I close the running form.
Can you please tell me how it would be more correct to open additional forms in PyQt5?

Answer 1

def start_window():
    from ui import Ui_MainWindow //здесь импотированна форма ui.py полученная через PyUIC5
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
  
ui.pushButton.clicked.connect(start_window)