input: Write a python function to generate a random sample of given size from a list of items.
  assert len(random_sample([1,2,3,4,5,6,7,8,9], 4))==4
  assert set(random_sample([1,2,3,4,5,6,7,8,9], 4)).issubset(set([1,2,3,4,5,6,7,8,9]))
  assert len(random_sample(['a','b','c','d','e','f'], 3))==3
output: import random
  
  def random_sample(items, size):
      return random.sample(items, size)