code: private void addInitial(G g) {
          Set<T> typeCounts = g.edgeTypes();
          LinkedList<Map.Entry<G,Integer>> graphs = typesToGraphs.get(typeCounts);
          if (graphs == null) {
              graphs = new LinkedList<Map.Entry<G,Integer>>();
              typesToGraphs.put(new HashSet<T>(typeCounts), graphs);
          }
  
          graphs.add(new SimpleEntry<G,Integer>(g, 0));
      }
docs: Adds an initial set of valid motifs to this counter with no counts.  This
  method enables the fixed-motif constructor to initialize the set of valid
  motifs prior to counting.