input: Write a function to find and return the greatest 2 numbers from a given list of integers. The function should return the two greatest numbers in the order of their appearance.
  
  
  def get_greatest_2(items):
   max1 = max2 = float('-inf')
   for item in items:
   if item > max1:
   max1, max2 = item, max1
   elif item > max2:
   max2 = item
   return max1, max2
  
  
  myList = [1, 5, 3, 7, 4, 7, 8, 9, 2, 10, 6, 8]
  assert get_greatest_2(myList) == (10, 9)
  
  myList = [10, 5, 3, 7, 4, 7, 8, 9, 2, 1, 6, 8]
  assert get_greatest_2(myList) == (10, 9)
  
  myList = [-1, -5, -3, -7, -4, -7, -8, -9, -2, -10, -6, -8]
  assert get_greatest_2(myList) == (-1, -2)
  
  myList = [1]
  assert get_greatest_2(myList) == (1, float('-inf'))
  
  myList = []
  assert get_greatest_2(myList) == (float('-inf'), float('-inf'))
  
output: def get_greatest_2(items):
      max1 = max2 = float('-inf')
      for item in items:
          if item > max1:
              max1, max2 = item, max1
          elif item > max2:
              max2 = item
      return max1, max2