copy doesn't work well

[aivision2020]

maybe it's a pybind11 issue? this test fails

pose = g2o.Isometry3d(np.eye(3), np.zeros(3))
assert pytest.approx(pose.rotation_matrix()) == np.eye(3)
pose_ = copy.deepcopy(pose)
assert pytest.approx(pose_.rotation_matrix()) == np.eye(3)

Thanks