def METHOD_NAME(
    api_client, checkout_with_item, voucher
):
    variables = {"promoCode": voucher.code}
    data = _mutate_checkout_add_promo_code(api_client, variables)
    assert len(data["errors"]) == 1
    assert not data["checkout"]
    assert data["errors"][0]["code"] == CheckoutErrorCode.GRAPHQL_ERROR.name