def METHOD_NAME(params):
    hypothesiser = params["hypothesiser"]
    all_tracks = params["all_tracks"]
    start_time = params["start"]
    stitcher2 = TrackStitcher(forward_hypothesiser=hypothesiser,
                              backward_hypothesiser=hypothesiser)
    stitched_tracks2, _ = stitcher2.stitch(all_tracks, start_time)
    no_stitched_tracks = len(stitched_tracks2)
    assert no_stitched_tracks == 3