# 普通：求函数运行时间

 def cal(l):

     start_time = time.time()

     res = 0

     for i in l:

         time.sleep(0.1)

         res+=i

     end_time = time.time()

     print('函数运行时间是%s'%(end_time-start_time))

     return res

 print(cal(range(20)))   # 函数运行时间是2.008193016052246  190

 import time

 def timmer(func):

     def wrapper(*args,**kwargs):

         start_time=time.time()

         res=func(*args,**kwargs)

         stop_time = time.time()

         print('函数运行时间是%s' %(stop_time-start_time))

         return res

     return wrapper

 @timmer

 def cal(l):

     res=0

     for i in l:

         time.sleep(0.1)

         res+=i

     return res

 res=cal(range(20))

 print(res)