Returns the n maximum elements from the provided list.
- Use 
sorted()to sort the list. - Use slice notation to get the specified number of elements.
 - Omit the second argument, 
n, to get a one-element list. - If 
nis greater than or equal to the provided list’s length, then return the original list (sorted in descending order). 
代码实现
def max_n(lst, n = 1):
  return sorted(lst, reverse = True)[:n]
使用样例
max_n([1, 2, 3]) # [3]
max_n([1, 2, 3], 2) # [3, 2]