input: Write a python function to find the minimum and maximum values in a list.
  assert min_max([-2, 15, 4, 8, 11]) == (-2, 15)
  assert min_max([1, 2, 3, 4, 5]) == (1, 5)
  assert min_max([99, -99, 0, 50, -50]) == (-99, 99)
output: def min_max(lst):
      return (min(lst), max(lst))