anchor.diff:  
     Iterable<JefeProject> get depthFirst;
   
  -//  Iterable<JefeProject> getDepthFirst(Set<JefeProject> visited);
  +  Iterable<JefeProject> getDepthFirst(Set<JefeProject> visited);
   
     Future processDepthFirst(
         process(JefeProject project, Iterable<JefeProject> dependencies));
  
positive.code: //      map/*<Option<JefeProject>>*/((c) => c.getProjectByName(projectName))
  //          .firstWhere((o) => o is Some, orElse: () => const None());
  
    Future processDepthFirst(
        process(JefeProject project, Iterable<JefeProject> dependencies)) async {
      await Future.forEach(
  
negative.code:     implements JefeProjectGraph {
    JefeProjectSet(Set<JefeProject> base) : super(base);
  
    JefeProjectSet get directDependencies => this;
  }
  
  