Hi all,

I have a PGroupedTable<A,B> and I want to aggregate / combine the values to produce a PCollection<C> - in other words, I need the type of the aggregate to be different to the original value type. 

What's the best approach? The combineValues method takes either an Aggregator or a CombineFn but as far as I can see, both of these assume the end result will be of the same type as the values. 

Have I missed something?