input: Write a function to randomize the elements of a given list of integers using the optimized Fisher-Yates algorithm. The function should return the randomized list. If the input list is empty, it should return an empty list.
  assert randomized_list([1, 2, 3, 4, 5])!= [1, 2, 3, 4, 5]
  assert randomized_list([10, 20, 30, 40])!= [10, 20, 30, 40]
  assert randomized_list([7])== [7]
  assert randomized_list([])== []
output: import random
  
  def randomized_list(lst):
      if not lst:
          return []
      for i in range(len(lst) - 1, 0, -1):
          j = random.randint(0, i)
          lst[i], lst[j] = lst[j], lst[i]
      return lst