return build();
    }
  }

  private static <K, V> ImmutableMap<K, V> fromEntryList(
      Collection<? extends Entry<? extends K, ? extends V>> entries) {
    return fromEntryList(/* throwIfDuplicateKeys= */ true, entries);
  }

  private static <K, V> ImmutableMap<K, V> fromEntryList(
      boolean throwIfDuplicateKeys, Collection<? extends Entry<? extends K, ? extends V>> entries) {