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 __new__(cls, *args, **kwargs):
        raise TypeError("Instances of {} are not allowed to be constructed!".format(cls.__name__))