':return: é®é¢åå»ºæ¶éŽ
:rtype: datetime.datetime'

@property
@check_soup('_creation_time')
def creation_time(self):

    logs = self._query_logs()
    time_string = logs[(-1)].find('div', class_='zm-item-meta').time['datetime']
    return datetime.strptime(time_string, '%Y-%m-%d    %H:%M:%S')
