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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 set_scrollbars_cb(self, w, tf):
 """This callback is invoked when the user checks the 'Use Scrollbars' box in the preferences pane."""

        scrollbars = 'on' if tf else 'off'
        self.t_.set(scrollbars=scrollbars)