@Override
  public Object getInitialAggregatedValue(byte[] rawValue) {
    Sketch<IntegerSummary> initialValue = deserializeAggregatedValue(rawValue);
    Union tupleUnion = new Union<>(_nominalEntries, new IntegerSummarySetOperations(_mode, _mode));
    tupleUnion.union(initialValue);
    return tupleUnion;
  }
@Test
  public void initialShouldParseASketch() {
    IntegerTupleSketchValueAggregator agg = new IntegerTupleSketchValueAggregator(IntegerSummary.Mode.Sum);
    assertEquals(toSketch(agg.getInitialAggregatedValue(sketchContaining("hello world", 1))).getEstimate(), 1.0);
  }