python 输出时间格式转换：
datetime： 输出格式为 class
如：datetime.datetime.now()
1. time class转换为time tuple类型
使用timetuple()
time = datetime.datetime.now()
time1 = time.timetuple()
2. timetuple转换为seconds格式
使用time模块的方法mktime()
time2 = time.mktime(time1)
下图为time模块的几种格式的转换方法:
官网链接：https://docs.python.org/2/library/time.html#module-time
| From | To | Use |
| seconds since the epoch | struct_time in UTC |
gmtime() |
| seconds since the epoch | struct_time in local time |
localtime() |
struct_time in UTC |
seconds since the epoch | calendar.timegm() |
struct_time in local time |
seconds since the epoch | mktime() |