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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 add_widget(self, widget):
 """Add the given widget to the tooltip :param widget: the widget to add :type widget: QtGui.QWidget :returns: None :rtype: None :raises: None """

        if self._buttons.get(widget):
            return
        btn = self.create_button(widget)
        cb = partial(self.focus_widget, w=widget)
        btn.clicked.connect(cb)
        self.layout().addWidget(btn)
        self._buttons[widget] = btn