PySide2 Lambda Binding Issue

I am working on a (fairly basic) feature in a PySide2 application. The application contains a list of checkboxes, and when a checkbox is checked, I need to append the index of the checkbox to a list. My unsuccessful attempt at this can be seen below...

checked = []

cb1 = QCheckBox('1')
cb2 = QCheckBox('2')
cb3 = QCheckBox('3')

cbs = [cb1, cb2, cb3]

for n, cb in enumerate(cbs):
    cb.stateChanged.connect(lambda: checked.append(n) if cb.isChecked() else checked.remove(n))

I have found that the issue here is with "late binding" as described in python's common gotchas. The value of n is always 2 whenever the checkbox is activated. However, I have tried using the following solutions from the docs which also have failed.

for n, cb in enumerate(cbs):
    cb.stateChanged.connect(lambda n=n: checked.append(n) if cb.isChecked() else checked.remove(n))

for n, cb in enumerate(cbs):
    cb.stateChanged.connect(lambda n=n, button=button: checked.append(n) if cb.isChecked() else checked.remove(n))

The first solution gives seemingly random and incorrect values for n, and the second somehow turns the button variable into an integer. In a case with only a few checkboxes I would consider setting these functions one-by-one but in the actual application there needs to be around 20 checkboxes. Any insight on this would be greatly appreciated!