@Override
	public final void coGroup(Iterable<IN1> first, Iterable<IN2> second, Collector<OUT> out) throws Exception {
		streamer.streamBufferWithGroups(first.iterator(), second.iterator(), out);
	}
@ Override public final void coGroup ( Iterable < IN1 > first , Iterable < IN2 > second , Collector < OUT > out ) throws Exception { streamer . streamBufferWithGroups ( first . iterator ( ) , second . iterator ( ) , out ) ; }
Calls the external python function.

@param first
@param second
@param out collector
@throws IOException