def test_invalid_scalar_index(adata, index):
    # https://github.com/theislab/anndata/issues/619
    with pytest.raises(IndexError, match=r".*index.* out of range\."):
        _ = adata[index]
def warn(txt, act, opt):
    if opt.get('display_examples'):
        print(txt + ":\n" + str(act))
    else:
        warn_once(txt)