text: from itertools import islice, chain
  
  
  def grouper_chunk(n, iterable):
      "grouper_chunk(3, '[1,2,3,4,5,6,7]') --> [1,2,3] [4,5,6] [7]"
      it = iter(iterable)
      while True:
          chunk = islice(it, n)
          try:
              first_el = next(chunk)
          except StopIteration:
              return
          yield chain((first_el,), chunk)
  