expected_raw_proposal_boxes = [[[0., 0., 0.5, 0.5], [0., 0.5, 0.5, 1.],
                                    [0.5, 0., 1., 0.5], [0.5, 0.5, 1., 1.]],
                                   [[0., 0., 0.5, 0.5], [0., 0.5, 0.5, 1.],
                                    [0.5, 0., 1., 0.5], [0.5, 0.5, 1., 1.]]]