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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 height_max(self, height_max):
 """Set the maximum height of the widget. Parameters height_max: None | float the maximum height of the widget. if None, maximum height is unbounded """

        if height_max is None:
            self._height_limits[1] = None
            return

        height_max = float(height_max)
        assert(0 <= self.height_min <= height_max)
        self._height_limits[1] = height_max
        self._update_layout()