StatsAccumulator accumulator = new StatsAccumulator();
    accumulator.addAll(values);
    return accumulator;
  }

  public void testCount() {
    assertThat(emptyAccumulator.count()).isEqualTo(0);
    assertThat(emptyAccumulatorByAddAllEmptyIterable.count()).isEqualTo(0);
    assertThat(emptyAccumulatorByAddAllEmptyStats.count()).isEqualTo(0);