input: Write a python function to reverse a list without using built-in functions.
  assert reverse_list_without_function([1, 2, 3, 4]) == [4, 3, 2, 1]
  assert reverse_list_without_function([10, 20, 30, 40]) == [40, 30, 20, 10]
  assert reverse_list_without_function(['a', 'b', 'c', 'd']) == ['d', 'c', 'b', 'a']
output: def reverse_list_without_function(lst):
      reversed_list = []
      for i in range(len(lst) - 1, -1, -1):
          reversed_list.append(lst[i])
      return reversed_list