How to use the haraka-net-utils.is_ip_in_str function in haraka-net-utils

const plugin = this;

    if (plugin.should_skip(connection, 'dynamic')) { return next(); }

    // Skip if no dots or an IP literal or address
    if (!/\./.test(helo)) {
        connection.results.add(plugin, {skip: 'dynamic(no dots)'});
        return next();
    }

    if (net_utils.get_ipany_re('^\\[?(?:IPv6:)?','\\]?$','').test(helo)) {
        connection.results.add(plugin, {skip: 'dynamic(literal)'});
        return next();
    }

    if (net_utils.is_ip_in_str(connection.remote.ip, helo)) {
        connection.results.add(plugin, {fail: 'dynamic'});
        if (plugin.cfg.reject.dynamic) {
            return next(DENY, 'HELO is dynamic');
        }
        return next();
    }

    connection.results.add(plugin, {pass: 'dynamic'});
    return next();
}