input: def get_greatest_2(items: List[int]) -> (int, int):
      """ Find the two greatest numbers in the given list of integers.
      >>> get_greatest_2([1, 5, 3, 7, 4, 7, 8, 9, 2, 10, 6, 8])
      (10, 9)
      """
output:     if len(items) < 2:
          raise ValueError("List must contain at least two elements")
      
      first_max = max(items[0], items[1])
      second_max = min(items[0], items[1])
      
      for num in items[2:]:
          if num > first_max:
              second_max = first_max
              first_max = num
          elif num > second_max:
              second_max = num
      
      return (first_max, second_max)