输出东八区的时间

    def before_month_lastday(ti,num):
        from dateutil.parser import parse
        today=dateutil.parser.parse(str(ti))

        #first = datetime.date(day=1, month=today.month, year=today.year)

        lastMonth = today - datetime.timedelta(days=num)

        def plus(k):
            if k<10:
                return '0'+str(k)
            else:
                return str(k)
        y=lastMonth.year
        m=lastMonth.month
        #d=lastMonth.day
        day=calendar.monthrange(y,m)[1]

        cc=str(y)+plus(m)+plus(day)
        bb=parse(cc)
        pacific = pytz.timezone('Asia/Shanghai')
        return pacific.localize(bb)