input: Write a python function to convert a list into a tuple.
  assert list_to_tuple([1, 2, 3, 4]) == (1, 2, 3, 4)
  assert list_to_tuple(['a', 'b', 'c']) == ('a', 'b', 'c')
  assert list_to_tuple([]) == ()
output: def list_to_tuple(lst):
      return tuple(lst)