docs: private PartitionVertexAggregate<M> getPartitioned(long vertexId) {
          assert idManager.isPartitionedVertex(vertexId);
          vertexId=getCanonicalId(vertexId);
          PartitionVertexAggregate<M> state = partitionVertices.get(vertexId);
          if (state==null) {
              partitionVertices.putIfAbsent(vertexId,new PartitionVertexAggregate<>(previousScopes));
              state = partitionVertices.get(vertexId);
          }
          return state;
      }