anchor.diff:      digraph:add_vertex(G, "c"),
       digraph:add_vertex(G, "d"),
       digraph:add_vertex(G, "e"),
  -    digraph:add_edge(G, "a", "b"),
  -    digraph:add_edge(G, "b", "c"),
  -    digraph:add_edge(G, "c", "d"),
  -    digraph:add_edge(G, "b", "b"),
  +    digraph_add_edge(G, "a", "b"),
  +    digraph_add_edge(G, "b", "c"),
  +    digraph_add_edge(G, "c", "d"),
  +    digraph_add_edge(G, "b", "b"),
       {LG = #louvain_graph{}, CleanupFn} = part_louvain:graph(
                                               digraph:vertices(G),
                                               [digraph:edge(G, E) ||
  
positive.code:     digraph:add_vertex(G, "c"),
      digraph:add_vertex(G, "d"),
      digraph:add_vertex(G, "e"),
      digraph:add_edge(G, "a", "b"),
      digraph:add_edge(G, "b", "c"),
      digraph:add_edge(G, "c", "d"),
      digraph:add_edge(G, "b", "b"),
      {LG = #louvain_graph{}, CleanupFn} = part_louvain:graph(
                                              digraph:vertices(G),
                                              [digraph:edge(G, E) ||
  
negative.code: 
  % Modularity increases with each layer of the dendrogram
  partition_modularity_increase() ->
      % trace(),
      G = digraph:new(),
      {Neighbors, Edges, _Nodes} = random_graph(G, 1000, 0.01),
      Dendrogram = part_louvain:dendrogram(
  