code: def cross(*sequences):
      """
      From: http://book.opensourceproject.org.cn/lamp/python/pythoncook2/opensource/0596007973/pythoncook2-chp-19-sect-9.html
      """
      # visualize an odometer, with "wheels" displaying "digits"...:
      wheels = map(iter, sequences)
      digits = [it.next() for it in wheels]
      while True:
          yield tuple(digits)
          for i in range(len(digits) - 1, -1, -1):
              try:
                  digits[i] = wheels[i].next()
                  break
              except StopIteration:
                  wheels[i] = iter(sequences[i])
                  digits[i] = wheels[i].next()
          else:
              break
  
label_desc: Use image node_id 2 for calling a global function with example usage: cross() without return types