input: 
  from typing import List
  
  def largest_three_numbers(numbers: List[int]) -> List[int]:
      """ Find the largest three numbers in a given list.
      >>> largest_three_numbers([1, 6, 3, 8, 7, 4])
      [6, 7, 8]
      """
      return sorted(numbers)[-3:]
  
output:     numbers.sort()
      return numbers[-3:]