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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 setup(name, path='log', enable_debug=False):
 """ Prepare a NestedSetup. :param name: the channel name :param path: the path where the logs will be written :param enable_debug: do we want to save the message at the DEBUG level :return a nested Setup """

    path_tmpl = os.path.join(path, '{name}_{level}.log')
    info = path_tmpl.format(name=name, level='info')
    warn = path_tmpl.format(name=name, level='warn')
    err = path_tmpl.format(name=name, level='err')
    crit = path_tmpl.format(name=name, level='crit')
    # a nested handler setup can be used to configure more complex setups
    setup = [
        # make sure we never bubble up to the stderr handler
        # if we run out of setup handling
        NullHandler(),
        # then write messages that are at least info to to a logfile
        TimedRotatingFileHandler(info, level='INFO', encoding='utf-8',
                                 date_format='%Y-%m-%d'),
        # then write messages that are at least warnings to to a logfile
        TimedRotatingFileHandler(warn, level='WARNING', encoding='utf-8',
                                 date_format='%Y-%m-%d'),
        # then write messages that are at least errors to to a logfile
        TimedRotatingFileHandler(err, level='ERROR', encoding='utf-8',
                                 date_format='%Y-%m-%d'),
        # then write messages that are at least critical errors to to a logfile
        TimedRotatingFileHandler(crit, level='CRITICAL', encoding='utf-8',
                                 date_format='%Y-%m-%d'),
    ]
    if enable_debug:
        debug = path_tmpl.format(name=name, level='debug')
        setup.insert(1, TimedRotatingFileHandler(debug, level='DEBUG',
                     encoding='utf-8', date_format='%Y-%m-%d'))
    if src_server is not None and smtp_server is not None \
            and smtp_port != 0 and len(dest_mails) != 0:
        mail_tmpl = '{name}_error@{src}'
        from_mail = mail_tmpl.format(name=name, src=src_server)
        subject = 'Error in {}'.format(name)
        # errors should then be delivered by mail and also be kept
        # in the application log, so we let them bubble up.
        setup.append(MailHandler(from_mail, dest_mails, subject,
                                 level='ERROR', bubble=True,
                                 server_addr=(smtp_server, smtp_port)))

    return NestedSetup(setup)