python习题：封装一个日志模块

import logging
from logging import handlers

class Logger(object):
    level_relations = {
        'debug': logging.DEBUG,
        'info': logging.INFO,
        'warning': logging.WARN,
        'error': logging.ERROR,
        'crit': logging.CRITICAL
    }
    def __init__(self,filename,level='info',when='d',back_count=3,fmt='%(asctime)s - %(pathname)s[line:%(lineno)d] - %(levelname)s: %(message)s'):
        self.logger = logging.getLogger(filename)
        format_str = logging.Formatter(fmt) # 设置日志格式
        self.logger.setLevel(self.level_relations.get(level)) # 设置日志级别，需要根据key去字典里取value
        sh = logging.StreamHandler()
        sh.setFormatter(format_str)
        th = handlers.TimedRotatingFileHandler(filename=filename,
                                               when=when,
                                               backupCount=back_count,
                                               encoding='utf-8'
                                               )
        th.setFormatter(format_str)
        self.logger.addHandler(sh)
        self.logger.addHandler(th)


if __name__ == '__main__':
    log = Logger('sherry.log')
    log.logger.debug('立刻走= like you')
    log.logger.info('info=infomation')
    log.logger.warning('ssssss=warning')
    log.logger.error('error')