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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def _identify_os(self, msg):
        '''
        Using the prefix of the syslog message,
        we are able to identify the operating system and then continue parsing.
        '''
        ret = []
        for dev_os, data in self.compiled_prefixes.items():
            # TODO Should we prevent attepmting to determine the OS for the blacklisted?
            # [mircea] I think its good from a logging perspective to know at least that
            #   that the server found the matching and it tells that it won't be processed
            #   further. Later, we could potentially add an option to control this.
            log.debug('Matching under %s', dev_os)
            msg_dict = self._identify_prefix(msg, data)
            if msg_dict:
                log.debug('Adding %s to list of matched OS', dev_os)
                ret.append((dev_os, msg_dict))
            else:
                log.debug('No match found for %s', dev_os)
        if not ret:
            log.debug('Not matched any OS, returning original log')
            msg_dict = {'message': msg}
            ret.append((None, msg_dict))
        return ret