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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 update_boxes(self, box_pos, box_size):
 """Set the box bounds from specified box positions and sizes."""

        assert box_pos.shape == (self.n_boxes, 2)
        assert len(box_size) == 2
        self.box_bounds = _get_boxes(box_pos,
                                     size=box_size,
                                     keep_aspect_ratio=self.keep_aspect_ratio,
                                     )