code: @Override
      public Set<KamNode> findNode(Pattern labelPattern, NodeFilter filter) {
          Set<KamNode> results = new LinkedHashSet<KamNode>();
          for (KamNode node : getNodes()) {
              boolean passedFilter = (filter == null || filter.accept(node));
  
              if (passedFilter && labelPattern.matcher(node.getLabel()).matches()) {
                  results.add(node);
              }
          }
          return results;
      }
docs: {@inheritDoc}