input: Write a python function to return the top three largest numbers in a list.
  assert top_three([7, 13, 5, 8, 50, 11, 64, 48]) == [64, 50, 48]
  assert top_three([1, 2, 3, 4, 5]) == [5, 4, 3]
  assert top_three([10, 10, 10, 10, 10]) == [10, 10, 10]
output: def top_three(numbers):
      return sorted(numbers, reverse=True)[:3]