code: def map_many(f, *nests):
      n0, *nests = nests
      iters = [flatten(n) for n in nests]
  
      def g(first):
          return f([first] + [next(i) for i in iters])
  
      return map(g, n0)
  
label_desc: Use image node_id 4 for calling a global function with example usage: map_many(f) and returns: map, f