input: Write a function to find the largest three numbers in a list. The function should return a list of these three numbers in descending order. If the list has fewer than three elements, the function should return all the elements in descending order.
  
  assert find_largest_three([1, 6, 3, 8, 7, 4])==[8, 7, 6]
  assert find_largest_three([4, 3, 1])==[4, 3, 1]
  assert find_largest_three([5])==[5]
  assert find_largest_three([])==[]
  assert find_largest_three([10, 20, 30, 40])==[40, 30, 20]
output: def find_largest_three(lst):
      return sorted(lst, reverse=True)[:3]