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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 diagonalSize(self):
 """Get the length of the diagonal of actor bounding box."""

        b = self.polydata().GetBounds()
        return np.sqrt((b[1] - b[0]) ** 2 + (b[3] - b[2]) ** 2 + (b[5] - b[4]) ** 2)