});
    }

    private static <T> Map<AccessorKey, T> diff(Map<AccessorKey, T> first, Map<AccessorKey, T> second) {
        return first.entrySet().stream()
            .filter(e -> !second.containsKey(e.getKey()))
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
    }