How to use the certbot.compat.os function in certbot

def abs_path(self, path):
        """Converts a relative path to an absolute path relative to the root.
        Does nothing for paths that are already absolute.

        :param str path: The path
        :returns: The absolute path
        :rtype: str

        """
        if not os.path.isabs(path):
            return os.path.normpath(os.path.join(self.root, path))
        return os.path.normpath(path)

def acquire(self):
        # type: () -> None
        """Acquire the lock."""
        while self._fd is None:
            # Open the file
            fd = filesystem.open(self._path, os.O_CREAT | os.O_WRONLY, 0o600)
            try:
                self._try_lock(fd)
                if self._lock_success(fd):
                    self._fd = fd
            finally:
                # Close the file if it is not the required one
                if self._fd is None:
                    os.close(fd)

:param client: Client object
    :type client: client.Client

    :returns: `cert_path` and `fullchain_path` as absolute paths to the actual files
    :rtype: `tuple` of `str`

    """
    csr, _ = config.actual_csr
    cert, chain = le_client.obtain_certificate_from_csr(csr)
    if config.dry_run:
        logger.debug(
            "Dry run: skipping saving certificate to %s", config.cert_path)
        return None, None
    cert_path, _, fullchain_path = le_client.save_certificate(
        cert, chain, os.path.normpath(config.cert_path),
        os.path.normpath(config.chain_path), os.path.normpath(config.fullchain_path))
    return cert_path, fullchain_path

def determine_user_agent(config):
    """
    Set a user_agent string in the config based on the choice of plugins.
    (this wasn't knowable at construction time)

    :returns: the client's User-Agent string
    :rtype: `str`
    """

    # WARNING: To ensure changes are in line with Certbot's privacy
    # policy, talk to a core Certbot team member before making any
    # changes here.
    if config.user_agent is None:
        ua = ("CertbotACMEClient/{0} ({1}; {2}{8}) Authenticator/{3} Installer/{4} "
              "({5}; flags: {6}) Py/{7}")
        if os.environ.get("CERTBOT_DOCS") == "1":
            cli_command = "certbot(-auto)"
            os_info = "OS_NAME OS_VERSION"
            python_version = "major.minor.patchlevel"
        else:
            cli_command = cli.cli_command
            os_info = util.get_os_info_ua()
            python_version = platform.python_version()
        ua = ua.format(certbot.__version__, cli_command, os_info,
                       config.authenticator, config.installer, config.verb,
                       ua_flags(config), python_version,
                       "; " + config.user_agent_comment if config.user_agent_comment else "")
    else:
        ua = config.user_agent
    return ua

def _check_path_actions(self, filepath):
        """Determine actions to take with a new augeas path

        This helper function will return a tuple that defines
        if we should try to append the new filepath to augeas
        parser paths, and / or remove the old one with more
        narrow matching.

        :param str filepath: filepath to check the actions for

        """

        try:
            new_file_match = os.path.basename(filepath)
            existing_matches = self.parser_paths[os.path.dirname(filepath)]
            if "*" in existing_matches:
                use_new = False
            else:
                use_new = True
            remove_old = new_file_match == "*"
        except KeyError:
            use_new = True
            remove_old = False
        return use_new, remove_old

def compare_file_modes(mode1, mode2):
    """Return true if the two modes can be considered as equals for this platform"""
    if os.name != 'nt':
        # Linux specific: standard compare
        return oct(stat.S_IMODE(mode1)) == oct(stat.S_IMODE(mode2))
    # Windows specific: most of mode bits are ignored on Windows. Only check user R/W rights.
    return (stat.S_IMODE(mode1) & stat.S_IREAD == stat.S_IMODE(mode2) & stat.S_IREAD
            and stat.S_IMODE(mode1) & stat.S_IWRITE == stat.S_IMODE(mode2) & stat.S_IWRITE)

possible_next_link = True
        while possible_next_link:
            possible_next_link = False
            if server_path in reused_servers:
                next_server_path = reused_servers[server_path]
                next_dir_path = link_func(next_server_path)
                if os.path.islink(next_dir_path) and os.readlink(next_dir_path) == dir_path:
                    possible_next_link = True
                    server_path = next_server_path
                    dir_path = next_dir_path

        # if there's not a next one up to delete, then delete me
        # and whatever I link to
        while os.path.islink(dir_path):
            target = os.readlink(dir_path)
            os.unlink(dir_path)
            dir_path = target

        return dir_path

"""
    if config.dry_run:
        _report_successful_dry_run(config)
        return

    assert cert_path and fullchain_path, "No certificates saved to report."

    expiry = crypto_util.notAfter(cert_path).date()
    reporter_util = zope.component.getUtility(interfaces.IReporter)
    # Print the path to fullchain.pem because that's what modern webservers
    # (Nginx and Apache2.4) will want.

    verbswitch = ' with the "certonly" option' if config.verb == "run" else ""
    privkey_statement = 'Your key file has been saved at:{br}{0}{br}'.format(
            key_path, br=os.linesep) if key_path else ""
    # XXX Perhaps one day we could detect the presence of known old webservers
    # and say something more informative here.
    msg = ('Congratulations! Your certificate and chain have been saved at:{br}'
           '{0}{br}{1}'
           'Your cert will expire on {2}. To obtain a new or tweaked version of this '
           'certificate in the future, simply run {3} again{4}. '
           'To non-interactively renew *all* of your certificates, run "{3} renew"'
           .format(fullchain_path, privkey_statement, expiry, cli.cli_command, verbswitch,
               br=os.linesep))
    reporter_util.add_message(msg, reporter_util.MEDIUM_PRIORITY)

:raises errors.ConfigurationError: if cert name and domains mismatch

    """
    if config.renew_with_new_domains:
        return

    added, removed = _get_added_removed(new_domains, old_domains)

    msg = ("You are updating certificate {0} to include new domain(s): {1}{br}{br}"
           "You are also removing previously included domain(s): {2}{br}{br}"
           "Did you intend to make this change?".format(
               certname,
               _format_list("+", added),
               _format_list("-", removed),
               br=os.linesep))
    obj = zope.component.getUtility(interfaces.IDisplay)
    if not obj.yesno(msg, "Update cert", "Cancel", default=True):
        raise errors.ConfigurationError("Specified mismatched cert name and domains.")

:param list prepared: List of `~.PluginEntryPoint`.
    :param str question: Question to be presented to the user.

    :returns: Plugin entry point chosen by the user.
    :rtype: `~.PluginEntryPoint`

    """
    opts = [plugin_ep.description_with_name +
            (" [Misconfigured]" if plugin_ep.misconfigured else "")
            for plugin_ep in prepared]
    names = set(plugin_ep.name for plugin_ep in prepared)

    while True:
        disp = z_util(interfaces.IDisplay)
        if "CERTBOT_AUTO" in os.environ and names == set(("apache", "nginx")):
            # The possibility of being offered exactly apache and nginx here
            # is new interactivity brought by https://github.com/certbot/certbot/issues/4079,
            # so set apache as a default for those kinds of non-interactive use
            # (the user will get a warning to set --non-interactive or --force-interactive)
            apache_idx = [n for n, p in enumerate(prepared) if p.name == "apache"][0]
            code, index = disp.menu(question, opts, default=apache_idx)
        else:
            code, index = disp.menu(question, opts, force_interactive=True)

        if code == display_util.OK:
            plugin_ep = prepared[index]
            if plugin_ep.misconfigured:
                z_util(interfaces.IDisplay).notification(
                    "The selected plugin encountered an error while parsing "
                    "your server configuration and cannot be used. The error "
                    "was:\n\n{0}".format(plugin_ep.prepare()), pause=False)