docs: private String formatNode(PatriciaTrie.PatriciaNode<V> node, int bit, KeyMapper<String> keyMapper,
                      boolean formatBitString) {
          if (node.getBit() <= bit) {
              return "";
          } else {
              StringBuffer buffer = new StringBuffer();
              buffer.append("\"");
              buffer.append(getNodeId(node));
              buffer.append("\"");
              buffer.append(" [ ");
              buffer.append("label=");
              buffer.append(formatNodeLabel(node, keyMapper, formatBitString));
              buffer.append(" ]");
              buffer.append("\n");
  
              buffer.append(formatPointer(node, node.getLeft(), "l", "sw"));
              buffer.append(formatPointer(node, node.getRight(), "r", "se"));
  
              buffer.append(formatNode(node.getLeft(), node.getBit(), keyMapper, formatBitString));
              buffer.append(formatNode(node.getRight(), node.getBit(), keyMapper, formatBitString));
  
              return buffer.toString();
          }
      }