def test_iadd(self, evt):
        rval = event.ReturnValue(append_events=[evt])
        rval2 = event.ReturnValue(eat=True, append_events=[evt])
        rset = event.ResultSet()

        rset += rval
        rset += rval2
        rset += None
        assert rset.eat
        assert rset.append_events == [evt, evt]
def draw_axis(img, charuco_corners, charuco_ids, board):
    vecs = np.load("./calib.npz")  # I already calibrated the camera
    mtx, dist, _, _ = [vecs[i] for i in ('mtx', 'dist', 'rvecs', 'tvecs')]
    ret, rvec, tvec = cv2.aruco.estimatePoseCharucoBoard(
        charuco_corners, charuco_ids, board, mtx, dist)
    if ret is not None and ret is True:
        cv2.aruco.drawAxis(img, mtx, dist, rvec, tvec, 0.1)