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 deserialize(self, value):
        value = decode(value).strip()
        validators.validate_required(value, self._required)
        if not value:
            return None
        validators.validate_choice(value, self._choices)
        return value