input: Write a function that shuffles a given list using Python's `random` module. The function should use `random.shuffle()` to reorder the elements of the list in place and then return the shuffled list. If the input list is empty, the function should return the empty list unchanged.
  
  assert shuffle_list([1, 2, 3, 4, 5])  # Output will vary due to shuffle
  assert shuffle_list(['a', 'b', 'c'])   # Output will vary due to shuffle
  assert shuffle_list([7, 3, 9, 1])      # Output will vary due to shuffle
  assert shuffle_list([]) == []
  assert shuffle_list(['apple', 'banana', 'cherry'])  # Output will vary due to shuffle
output: def shuffle_list(lst):
      if lst:
          random.shuffle(lst)
      return lst