How to use the rss2email.error function in rss2email

port = config.getint(section, 'smtp-port')

    _LOG.debug('sending message to {} via {}'.format(recipient, server))
    ssl = config.getboolean(section, 'smtp-ssl')
    smtp_auth = config.getboolean(section, 'smtp-auth')
    try:
        if ssl or smtp_auth:
            context = _ssl.create_default_context()
        if ssl:
            smtp = _smtplib.SMTP_SSL(host=server, port=port, context=context)
        else:
            smtp = _smtplib.SMTP(host=server, port=port)
    except KeyboardInterrupt:
        raise
    except Exception as e:
        raise _error.SMTPConnectionError(server=server) from e
    if smtp_auth:
        username = config.get(section, 'smtp-username')
        password = config.get(section, 'smtp-password')
        try:
            if not ssl:
                smtp.starttls(context=context)
            smtp.login(username, password)
        except KeyboardInterrupt:
            raise
        except Exception as e:
            raise _error.SMTPAuthenticationError(
                server=server, username=username)
    smtp.send_message(message, sender, recipient.split(','))
    smtp.quit()

'US-ASCII'
    >>> guess_encoding('α', encodings=('US-ASCII', 'UTF-8'))
    'UTF-8'
    >>> guess_encoding('α', encodings=('US-ASCII', 'ISO-8859-1'))
    Traceback (most recent call last):
      ...
    rss2email.error.NoValidEncodingError: no valid encoding for α in ('US-ASCII', 'ISO-8859-1')
    """
    for encoding in encodings:
        try:
            string.encode(encoding)
        except (UnicodeError, LookupError):
            pass
        else:
            return encoding
    raise _error.NoValidEncodingError(string=string, encodings=encodings)

if ssl:
        imap = _imaplib.IMAP4_SSL(server, port)
    else:
        imap = _imaplib.IMAP4(server, port)
    try:
        if config.getboolean(section, 'imap-auth'):
            username = config.get(section, 'imap-username')
            password = config.get(section, 'imap-password')
            try:
                if not ssl:
                    imap.starttls()
                imap.login(username, password)
            except KeyboardInterrupt:
                raise
            except Exception as e:
                raise _error.IMAPAuthenticationError(
                    server=server, port=port, username=username)
        mailbox = config.get(section, 'imap-mailbox')
        date = _imaplib.Time2Internaldate(_time.localtime())
        message_bytes = _flatten(message)
        imap.append(mailbox, None, date, message_bytes)
    finally:
        imap.logout()

def new(feeds, args):
    "Create a new feed database."
    if args.email:
        _LOG.info('set the default target email to {}'.format(args.email))
        feeds.config['DEFAULT']['to'] = args.email
    if _os.path.exists(feeds.configfiles[-1]):
        raise _error.ConfigAlreadyExistsError(feeds=feeds)
    feeds.save()

def index(self, index):
        if isinstance(index, int):
            try:
                return self[index]
            except IndexError as e:
                raise _error.FeedIndexError(index=index, feeds=self) from e
        elif isinstance(index, str):
            try:
                index = int(index)
            except ValueError:
                pass
            else:
                return self.index(index)
            for feed in self:
                if feed.name == index:
                    return feed
        try:
            super(Feeds, self).index(index)
        except (IndexError, ValueError) as e:
            raise _error.FeedIndexError(index=index, feeds=self) from e

def _load_feeds(self, lock, require):
        _LOG.debug('load feed data from {}'.format(self.datafile))
        if not _os.path.exists(self.datafile):
            if require:
                raise _error.NoDataFile(feeds=self)
            _LOG.info('feed data file not found at {}'.format(self.datafile))
            _LOG.debug('creating an empty data file')
            dirname = _os.path.dirname(self.datafile)
            if dirname and not _os.path.isdir(dirname):
                _os.makedirs(dirname, mode=0o700, exist_ok=True)
            with _codecs.open(self.datafile, 'w', self.datafile_encoding) as f:
                self._save_feed_states(feeds=[], stream=f)
        try:
            self._datafile_lock = _codecs.open(
                self.datafile, 'r', self.datafile_encoding)
        except IOError as e:
            raise _error.DataFileError(feeds=self) from e

        locktype = 0
        if lock and UNIX:
            locktype = _fcntl.LOCK_SH

def __call__(self, *args, **kwargs):
        self._args = args
        self._kwargs = kwargs
        self.start()
        self.join(self.timeout)
        if self.error:
            raise _error.TimeoutError(
                time_limited_function=self) from self.error[1]
        elif self.is_alive():
            raise _error.TimeoutError(time_limited_function=self)
        return self.result