input: Write a python function to get the last element of a list.
  assert get_last_element([3, 5, 7, 9, 2]) == 2
  assert get_last_element([10, 20, 30, 40, 50]) == 50
  assert get_last_element([1, 3, 5, 7, 9]) == 9
output: def get_last_element(lst):
      return lst[-1]