python装饰器计算函数执行时间

import time
import logging
from functools import wraps
import datetime

log = logging.getLogger(__name__)

def count_time(func):
    @wraps(func)
    def _wrapper(*args, **kwargs):
        start_time = time.time()  # 程序开始时间
        log.info("task begin at: %s" %(datetime.datetime.fromtimestamp(start_time)))
        func()
        end_time = time.time()   # 程序结束时间
        log.info("task end at: %s" %(datetime.datetime.fromtimestamp(end_time)))
        total_time = end_time - start_time
        log.info('程序共计%s秒' % total_time)
　　return _wrapper