new_contents: import timeit
  import random
  
  for i in range (10000, 100000, 20000):
    t = timeit.Timer("random.randrange(%d) in x"%i, "from __main__ import random, x")
  
    x = list(range(i))
    list_time = t.timeit(number = 1000)
  
    x = {j:None for j in range(i)}
    dict_time = t.timeit(number = 1000)
  
    print "Counter: " + str(i) + "  List: " + str(list_time) + "  Dict: " + str(dict_time)
  
subject: Add python script to check big-O notation