code: public SortedMap<Integer, RangeSet> getRelationship(AbstractProject that) {
          TreeMap<Integer,RangeSet> r = new TreeMap<Integer,RangeSet>(REVERSE_INTEGER_COMPARATOR);
  
          checkAndRecord(that, r, this.getBuilds());
          // checkAndRecord(that, r, that.getBuilds());
  
          return r;
      }
docs: Gets the dependency relationship map between this project (as the source)
  and that project (as the sink.)
  
  @return
  can be empty but not null. build number of this project to the build
  numbers of that project.