def METHOD_NAME(self):
    if self.auth is not None:
        return self.auth
    if not self.host:
        return
    tp_kwargs = {}
    if app.TORRENT_AUTH_TYPE != 'none':
        tp_kwargs['authtype'] = app.TORRENT_AUTH_TYPE
    if not app.TORRENT_VERIFY_CERT:
        tp_kwargs['check_ssl_cert'] = False
    else:
        if app.SSL_CA_BUNDLE:
            tp_kwargs['check_ssl_cert'] = app.SSL_CA_BUNDLE
    try:
        if self.username and self.password:
            self.auth = RTorrent(self.host, self.username, self.password, True, tp_kwargs=tp_kwargs)
        else:
            self.auth = RTorrent(self.host, None, None, True)
    except Exception as error:  # No request/connection specific exception thrown.
        raise DownloadClientConnectionException(f'Unable to authenticate with rtorrent client: {error}')
    return self.auth