input: Write a function to find the top three largest numbers in a list.
  assert top_three([10, 8, 3, 11, 7, 14, 13]) == [14, 13, 11]
  assert top_three([4, 1, 6, 8, 2]) == [8, 6, 4]
  assert top_three([100, 99, 98, 97, 96]) == [100, 99, 98]
output: def top_three(numbers):
      return sorted(numbers, reverse=True)[:3]