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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def connect_checkable_button(instance, prop, widget):
 """ Connect a boolean callback property with a Qt button widget. Parameters instance : object The class instance that the callback property is attached to prop : str The name of the callback property widget : QtWidget The Qt widget to connect. This should implement the ``setChecked`` method and the ``toggled`` signal. """

    add_callback(instance, prop, widget.setChecked)
    widget.toggled.connect(partial(setattr, instance, prop))
    widget.setChecked(getattr(instance, prop) or False)