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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 bar_touched(self, bar, touch):
 """Start scrolling, and record where I started scrolling."""

        self.scrolling = True
        self._start_bar_pos_hint = get_pos_hint(bar.pos_hint, *bar.size_hint)
        self._start_touch_pos_hint = (
            touch.x / self.width,
            touch.y / self.height
        )
        self._start_bar_touch_hint = (
            self._start_touch_pos_hint[0] - self._start_bar_pos_hint[0],
            self._start_touch_pos_hint[1] - self._start_bar_pos_hint[1]
        )
        touch.grab(self)