docs: public <T extends Graph> T getGraph(Class<T> clazz, Weighting weighting) {
          if (clazz.equals(Graph.class))
              return (T) baseGraph;
  
          Collection<CHGraphImpl> chGraphs = getAllCHGraphs();
          if (chGraphs.isEmpty())
              throw new IllegalStateException("Cannot find graph implementation for " + clazz);
  
          if (weighting == null)
              throw new IllegalStateException("Cannot find CHGraph with null weighting");
  
          List<Weighting> existing = new ArrayList<>();
          for (CHGraphImpl cg : chGraphs) {
              if (cg.getWeighting() == weighting)
                  return (T) cg;
  
              existing.add(cg.getWeighting());
          }
  
          throw new IllegalStateException("Cannot find CHGraph for specified weighting: " + weighting + ", existing:" + existing);
      }