input: Write a function to find the minimum and maximum values in a list of numbers.
  assert get_min_max([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == (1, 10)
  assert get_min_max([10, 20, 45, 67, 84, 93]) == (10, 93)
  assert get_min_max([5, 7, 9, 8, 6, 4, 3]) == (3, 9)
output: def get_min_max(numbers):
      if not numbers:
          return None, None
      min_val = min(numbers)
      max_val = max(numbers)
      return min_val, max_val