docs: public static <K, V> JavaPairRDD<K, V> executeMap(
              final JavaPairRDD<Object, VertexWritable> graphRDD, final MapReduce<K, V, ?, ?, ?> mapReduce,
              final Configuration graphComputerConfiguration) {
          JavaPairRDD<K, V> mapRDD = graphRDD.mapPartitionsToPair(partitionIterator -> {
              KryoShimServiceLoader.applyConfiguration(graphComputerConfiguration);
              return new MapIterator<>(MapReduce.<MapReduce<K, V, ?, ?, ?>>createMapReduce(HadoopGraph.open(graphComputerConfiguration), graphComputerConfiguration), partitionIterator);
          });
          if (mapReduce.getMapKeySort().isPresent()){
              mapRDD = mapRDD.sortByKey(mapReduce.getMapKeySort().get(), true, 1);}
          return mapRDD;
      }