input: Write a python function to reverse a linked list.
  assert reverse_linkedlist([1, 2, 3, 4])==[4, 3, 2, 1]
  assert reverse_linkedlist([10, 20, 30])==[30, 20, 10]
  assert reverse_linkedlist([])==[]
output: def reverse_linkedlist(lst):
      return lst[::-1]