Change checkbox state to not checked when other checkbox is checked pyqt

I'm using Qt Designer and pyqt code to write an app.

I have a very simple question: in my UI I have 2 checkboxes and what I need is to set the first checkbox as always unchecked when the second checkbox is unchecked.

In other words the first checkbox can be checked only when the second checkbox is checked, but the second checkbox can be checked also if the first one is not checked.

In Qt Designer I have not find an easy way to do that with the Signals/Slots function.

I had a look in the Qt API and I tried to write some code:

class CreateRIVLayerDialog(QDialog, FORM_CLASS):
    def __init__(self, iface)

    # some more code here...

    if self.addCheckDB.isChecked():
        self.addCheck.setChecked(False)

but without results.

Does anybody have some hints?

Thanks