code: public Tuple<VortexAggregateFunction, VortexAggregatePolicy> put(
        final int aggregateFunctionId,
        final VortexAggregateFunction aggregateFunction,
        final VortexAggregatePolicy policy) {
      return aggregateFunctionMap.put(aggregateFunctionId, new Tuple<>(aggregateFunction, policy));
    }
docs: Associates an aggregate function ID with a {@link VortexAggregateFunction} and a {@link VortexAggregatePolicy}.