new_contents: import itertools
  
  itr1 = itertools.count(5)
  for i in itr1:
      print(i)
      if i == 1000:
          break
  
  itr2 = itertools.cycle("ABC")
  for i, j in enumerate(itr2):
      print(i, j)
      if i == 1000:
          break
  
  itr3 = itertools.chain("ABC", range(1, 2))
  for i in itr3:
      print(i)
  
  itr4 = itertools.compress("ABCDE", [1, 0, 1, 0, 1])
  for i in itr4:
      print(i)
  
  p = lambda x: x < 5
  l = [1, 3, 4, 5, 1, 4, 9, 1]
  itr5 = itertools.dropwhile(p, l)
  for i in itr5:
      print(i)
  
  itr6 = itertools.takewhile(p, l)
  for i in itr6:
      print(i)
  
  for k, g in itertools.groupby(sorted("AAAABBBBVVVVDDDDEEEEAAACC")):
      print(k, [i for i in g])
  
  tpls = [(2, 3), (3, 4)]
  itr7 = itertools.starmap(lambda x, y: x * y, tpls)
  [print(i) for i in itr7]
  
  ls = range(0, 3)
  tee1, tee2, = itertools.tee(ls)
  [print(i) for i in tee1]
  [print(i) for i in tee1]
  [print(i) for i in tee2]
  
subject: Add itertools.