code: private Hashable find(Range<Token> range)
      {
          try
          {
              return findHelper(root, new Range<Token>(fullRange.left, fullRange.right), range);
          }
          catch (StopRecursion e)
          {
              return new Leaf();
          }
      }
docs: Find the {@link Hashable} node that matches the given {@code range}.
  
  @param range Range to find
  @return {@link Hashable} found. If nothing found, return {@link Leaf} with null hash.