@CanIgnoreReturnValue
  CacheBuilderFactory withMaximumSizes(Set<Integer> maximumSizes) {
    this.maximumSizes = new LinkedHashSet<>(maximumSizes);
    return this;
  }

  @CanIgnoreReturnValue
  CacheBuilderFactory withExpireAfterWrites(Set<DurationSpec> durations) {
    this.expireAfterWrites = new LinkedHashSet<>(durations);
    return this;
  }

  @CanIgnoreReturnValue

        }
      };

  private CacheBuilderFactory factoryWithAllKeyStrengths() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();