input: Write a python function to find the maximum and minimum values in a list.
  assert find_max_min([5, 6, 10, -9, 3, 21]) == (21, -9)
  assert find_max_min([1, 2, 3, 4, 5]) == (5, 1)
  assert find_max_min([-1, -2, -3, -4, -5]) == (-1, -5)
  assert find_max_min([100, 200, 300, 400, 500]) == (500, 100)
output: def find_max_min(lst):
      return (max(lst), min(lst))