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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 get_extents(self, view, ranges, range_type='combined'):
 """Supply custom, static extents because radial heatmaps always have the same boundaries. """

        if range_type not in ('data', 'combined'):
            return (None,)*4
        lower = -self.radius_outer
        upper = 2 * self.max_radius + self.radius_outer
        return (lower, lower, upper, upper)