input: Write a function to find the largest three numbers in a list. The function should return a list of the three largest numbers in descending order.
  
  def find_largest_three(nums):
      return sorted(nums)[-3:]
  
  assert find_largest_three([1, 6, 3, 8, 7, 4])==[6, 7, 8]
  assert find_largest_three([9, 1, 5, 2, 8, 7])==[5, 7, 8]
  assert find_largest_three([10, 15, 20, 5, 1])==[10, 15, 20]
  assert find_largest_three([3, 2, 1])==[1, 2, 3]
  assert find_largest_three([])==[]
output: def find_largest_three(nums):
      if len(nums) < 3:
          return sorted(nums, reverse=True)
      return sorted(nums, reverse=True)[:3]