How to create a new window in PyQt5?

Question

Python

Good afternoon.
There is a main window created in Designer with a button. All this is saved in the test.ui file.
Also, a new empty QWidget class window was created in the Designer and saved to the test2.ui file.
The new window file test2.py contains:

def new_form():   
    new_window = uic.loadUi("interface2.ui")
    new_window.setWindowTitle("New form")
    new_window.show()

In the main window file test.py:

import test2
main_window.pushButton.clicked.connect(test2.new_form)

If you click on the button in the main window, a new window will open and immediately close. Can you please tell me how to make this window permanently displayed?

Answer 1

reason: the new_window variable dies as soon as the new_form() function ends (why? for the glory of Satan, of course!)
Solutions:
1) create some kind of global variable. But global variables are bad form (don't know why):

new_window = None
def new_form():   
    global new_window
    new_window = uic.loadUi("interface2.ui")
    new_window.setWindowTitle("New form")
    new_window.show()

2) create a variable global array of windows (this is how I do it - it's still "bad form" but then you can delete all the created windows at once in a loop, for example...) :

мой_список_окон = []
def new_form():   
    global мой_список_окон
    new_window = uic.loadUi("interface2.ui")
    new_window.setWindowTitle("New form")
    new_window.show()
    мой_список_окон.append(new_window)

3) assign new_window to main_window's child (ideologically correct):

def new_form(parent):   
    new_window = uic.loadUi("interface2.ui")
    new_window.setWindowTitle("New form")
    new_window.show()
    new_window.setParent(parent)

import test2
main_window.pushButton.clicked.connect(lambda: test2.new_form(main_window))

4) new_window must be a variable of an object that is guaranteed not to be deleted (I don't know about the ideology... all options are correct. ):

def new_form(parent):   
    parent.new_window = uic.loadUi("interface2.ui")
    parent.new_window.setWindowTitle("New form")
    parent.new_window.show()


import test2
main_window.pushButton.clicked.connect(lambda: test2.new_form(main_window))