code: def helper2(n, length):
      if n == 0:
          return [""]
      if n == 1:
          return ["0", "8", "1"]
      mids = helper(n - 2, length)
      res = []
      for mid in mids:
          if n != length:
              res.append("0" + mid + "0")
          res.append("1" + mid + "1")
          res.append("6" + mid + "9")
          res.append("9" + mid + "6")
          res.append("8" + mid + "8")
      return res
  
label_desc: Use image node_id 4 for calling a global function with example usage: helper2(n, length) and returns: res, list, list