input: Write a python function to add an item to the beginning of a list.
  assert add_item_to_beginning([2, 3, 4], 1) == [1, 2, 3, 4]
  assert add_item_to_beginning(['b', 'c'], 'a') == ['a', 'b', 'c']
  assert add_item_to_beginning([], 'first') == ['first']
output: def add_item_to_beginning(lst, item):
      return [item] + lst