code: private long learn(PrintStream out, List<AssociationRule> list, int[] itemset, int size, Node node, double confidence) {
          long n = 0;
          if (node.children == null) {
              return n;
          }
  
          for (int i = 0; i < size; i++) {
              if (node.children[i] != null) {
                  int[] newItemset = FPGrowth.insert(itemset, node.children[i].id);
                  // Generate ARs for current large itemset
                  n += learn(out, list, newItemset, node.children[i].support, confidence);
                  // Continue generation process
                  n += learn(out, list, newItemset, i, node.children[i], confidence);
              }
          }
          
          return n;
      }
docs: Generates association rules from a T-tree.
  @param itemset the label for a T-tree node as generated sofar.
  @param size the size of the current array level in the T-tree.
  @param node the current node in the T-tree.
  @param confidence the confidence threshold for association rules.