input: Write a python function to find the minimum and maximum numbers in a list.
  assert find_min_max([5, 2, 7, 9]) == (2, 9)
  assert find_min_max([10, 3, 5, 1, 9]) == (1, 10)
  assert find_min_max([-1, -5, -3, -4]) == (-5, -1)
output: def find_min_max(numbers):
      return (min(numbers), max(numbers))