import logging
NOTICE = 25
logging.addLevelName(NOTICE, "NOTICE")
def notice(self, message, *args, **kws):
    if self.isEnabledFor(NOTICE):
        self._log(NOTICE, message, args, **kws)
logging.Logger.notice = notice

spam (5)
 verbose (15)
 notice (25)
 success (35)

import logging
def _custom_log_level(level_no, level_name):
    logging.addLevelName(level_no, level_name)
    def proxy_level(self, message, *args, **kwargs):
        if self.isEnabledFor(level_no):
            self._log(level_no, message, *args, **kwargs)
    return proxy_level

logging.Logger.notice = _custom_log_level(25, 'NOTICE')
logging.Logger.spam = _custom_log_level(5, 'SPAM')

verbose = _custom_log_level(15, 'VERBOSE')
   verbose.__name__ = 'verbose'
   logging.Logger.verbose = verbose