code: @Override
      public void add(ImprintNode... nodes) {
          Util.notNull(nodes, "Nodes");
          for (ImprintNode node : nodes) {
              add(node);
          }
      }
docs: Adds a new list of leaves to the binary tree.
  
  @param nodes a list of leaves to be added to the tree, must not be null.
  @throws IllegalArgumentException if node level is greater than 0.