input: Write a function to shuffle a list of numbers. The function should return the shuffled list. If the input list is empty, the function should return an empty list.
  assert shuffle_list([1, 2, 3, 4, 5])==[3, 5, 2, 4, 1]
  assert shuffle_list([])==[]
  assert shuffle_list([7, 8, 9, 10])==[9, 7, 10, 8]
output: import random
  
  def shuffle_list(lst):
      if not lst:
          return []
      shuffled = lst[:]
      random.shuffle(shuffled)
      return shuffled