code: @Override
      public KamNode findNode(Integer kamNodeId, NodeFilter filter) {
          final KamNode kamNode = idNodeMap.get(kamNodeId);
  
          if (kamNode == null) {
              return null;
          }
  
          if (filter != null) {
              if (!filter.accept(kamNode)) {
                  return null;
              }
          }
  
          return kamNode;
      }
docs: {@inheritDoc}