input: 
  def get_greatest_2(items: list) -> tuple:
      """
      Optimize the Python algorithm to find the greatest 2 numbers from a list of integers.
      >>> get_greatest_2([1, 5, 3, 7, 4, 7, 8, 9, 2, 10, 6, 8])
      (10, 9)
      >>> get_greatest_2([-1, -5, 3, -7, -4, -7, 8, -9, 2, -10, 6, -8])
      (8, 6)
      """
      max1 = max2 = float('-inf')
      for item in items:
          if item > max1:
              max1, max2 = item, max1
          elif item > max2:
              max2 = item
      return max1, max2
  
output:     max1 = max2 = float('-inf')
      for item in items:
          if item > max1:
              max1, max2 = item, max1
          elif item > max2:
              max2 = item
      return max1, max2