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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 a Widget as a managed child of this Widget. The child will be automatically positioned and sized to fill the entire space inside this Widget (unless _update_child_widgets is redefined). Parameters widget : instance of Widget The widget to add. Returns ------- widget : instance of Widget The widget. """

        self._widgets.append(widget)
        widget.parent = self
        self._update_child_widgets()
        return widget