def test_view_retains_ndarray_subclass():
    adata = ad.AnnData(np.zeros((10, 10)))
    adata.obsm["foo"] = np.zeros((10, 5)).view(NDArraySubclass)

    view = adata[:5, :]

    assert isinstance(view.obsm["foo"], NDArraySubclass)
    assert view.obsm["foo"].shape == (5, 5)
def kth(root, k):
    if k < size(root.left):
        return kth(root.left, k)
    elif k > size(root.left):
        return kth(root.right, k - size(root.left) - 1)
    return root.key