@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

            return builder.build(identityLoader());
          }
        });
  }

  private CacheBuilderFactory cacheFactory() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))

        }
      };

  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();

import static java.util.concurrent.TimeUnit.DAYS;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.cache.CacheBuilderFactory.DurationSpec;
import com.google.common.cache.LocalCache.Strength;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;

import static java.util.concurrent.TimeUnit.DAYS;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Function;
import com.google.common.cache.CacheBuilderFactory.DurationSpec;
import com.google.common.cache.LocalCache.Strength;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;