input: Write a function to find the largest three numbers in a list. If the list has fewer than three numbers, return all the numbers.
  def largest_three_numbers(nums):
      return sorted(nums)[-3:]
  
  assert largest_three_numbers([1, 6, 3, 8, 7, 4])==[6, 7, 8]
  assert largest_three_numbers([9, 3])==[3, 9]
  assert largest_three_numbers([5, 2, 7, 1, 9])==[5, 7, 9]
  assert largest_three_numbers([10])==[10]
  assert largest_three_numbers([])==[]
output: def largest_three_numbers(nums):
      return sorted(nums)[-3:]