How to use the sshuttle.helpers.debug2 function in sshuttle

def test_debug2_nop(mock_stderr, mock_stdout):
    sshuttle.helpers.debug2("message")
    assert mock_stdout.mock_calls == []
    assert mock_stderr.mock_calls == []

def udp_req(channel, cmd, data):
        debug2('Incoming UDP request channel=%d, cmd=%d\n' % (channel, cmd))
        if cmd == ssnet.CMD_UDP_DATA:
            (dstip, dstport, data) = data.split(b(','), 2)
            dstport = int(dstport)
            debug2('is incoming UDP data. %r %d.\n' % (dstip, dstport))
            h = udphandlers[channel]
            h.send((dstip, dstport), data)
        elif cmd == ssnet.CMD_UDP_CLOSE:
            debug2('is incoming UDP close\n')
            h = udphandlers[channel]
            h.ok = False
            del mux.channels[channel]

if line.startswith('HOST '):
                (name, ip) = line[5:].strip().split(',', 1)
                hostmap[name] = ip
                debug2('firewall manager: setting up /etc/hosts.\n')
                rewrite_etc_hosts(hostmap, port_v6 or port_v4)
            elif line:
                if not method.firewall_command(line):
                    raise Fatal('firewall: expected command, got %r' % line)
            else:
                break
    finally:
        try:
            sdnotify.send(sdnotify.stop())
            debug1('firewall manager: undoing changes.\n')
        except BaseException:
            debug2('An error occurred, ignoring it.')

        try:
            if subnets_v6 or nslist_v6:
                debug2('firewall manager: undoing IPv6 changes.\n')
                method.restore_firewall(port_v6, socket.AF_INET6, udp, user)
        except BaseException:
            try:
                debug1("firewall manager: "
                       "Error trying to undo IPv6 firewall.\n")
                for line in traceback.format_exc().splitlines():
                    debug1("---> %s\n" % line)
            except BaseException:
                debug2('An error occurred, ignoring it.')

        try:
            if subnets_v4 or nslist_v4:

def udp_req(channel, cmd, data):
        debug2('Incoming UDP request channel=%d, cmd=%d\n' % (channel, cmd))
        if cmd == ssnet.CMD_UDP_DATA:
            (dstip, dstport, data) = data.split(b(','), 2)
            dstport = int(dstport)
            debug2('is incoming UDP data. %r %d.\n' % (dstip, dstport))
            h = udphandlers[channel]
            h.send((dstip, dstport), data)
        elif cmd == ssnet.CMD_UDP_CLOSE:
            debug2('is incoming UDP close\n')
            h = udphandlers[channel]
            h.ok = False
            del mux.channels[channel]

def onhostlist(hostlist):
        debug2('got host list: %r\n' % hostlist)
        for line in hostlist.strip().split():
            if line:
                name, ip = line.split(b',', 1)
                fw.sethostip(name, ip)
    mux.got_host_list = onhostlist

def udp_req(channel, cmd, data):
        debug2('Incoming UDP request channel=%d, cmd=%d\n' % (channel, cmd))
        if cmd == ssnet.CMD_UDP_DATA:
            (dstip, dstport, data) = data.split(b(','), 2)
            dstport = int(dstport)
            debug2('is incoming UDP data. %r %d.\n' % (dstip, dstport))
            h = udphandlers[channel]
            h.send((dstip, dstport), data)
        elif cmd == ssnet.CMD_UDP_CLOSE:
            debug2('is incoming UDP close\n')
            h = udphandlers[channel]
            h.ok = False
            del mux.channels[channel]

def got_packet(self, channel, cmd, data):
        debug2('<  channel=%d cmd=%s len=%d\n'
               % (channel, cmd_to_name.get(cmd, hex(cmd)), len(data)))
        if cmd == CMD_PING:
            self.send(0, CMD_PONG, data)
        elif cmd == CMD_PONG:
            debug2('received PING response\n')
            self.too_full = False
            self.fullness = 0
        elif cmd == CMD_EXIT:
            self.ok = False
        elif cmd == CMD_TCP_CONNECT:
            assert(not self.channels.get(channel))
            if self.new_channel:
                self.new_channel(channel, data)
        elif cmd == CMD_DNS_REQ:
            assert(not self.channels.get(channel))
            if self.got_dns_req:
                self.got_dns_req(channel, data)
        elif cmd == CMD_UDP_OPEN:
            assert(not self.channels.get(channel))
            if self.got_udp_open:
                self.got_udp_open(channel, data)

rewrite_etc_hosts(hostmap, port_v6 or port_v4)
            elif line:
                if not method.firewall_command(line):
                    raise Fatal('firewall: expected command, got %r' % line)
            else:
                break
    finally:
        try:
            sdnotify.send(sdnotify.stop())
            debug1('firewall manager: undoing changes.\n')
        except BaseException:
            debug2('An error occurred, ignoring it.')

        try:
            if subnets_v6 or nslist_v6:
                debug2('firewall manager: undoing IPv6 changes.\n')
                method.restore_firewall(port_v6, socket.AF_INET6, udp, user)
        except BaseException:
            try:
                debug1("firewall manager: "
                       "Error trying to undo IPv6 firewall.\n")
                for line in traceback.format_exc().splitlines():
                    debug1("---> %s\n" % line)
            except BaseException:
                debug2('An error occurred, ignoring it.')

        try:
            if subnets_v4 or nslist_v4:
                debug2('firewall manager: undoing IPv4 changes.\n')
                method.restore_firewall(port_v4, socket.AF_INET, udp, user)
        except BaseException:
            try:

else:
                raise e

    debug2('\n')
    if not bound:
        assert(last_e)
        raise last_e
    tcp_listener.listen(10)
    tcp_listener.print_listening("TCP redirector")
    if udp_listener:
        udp_listener.print_listening("UDP redirector")

    bound = False
    if required.dns:
        # search for spare port for DNS
        debug2('Binding DNS:')
        ports = range(12300, 9000, -1)
        for port in ports:
            debug2(' %d' % port)
            if port in used_ports:
                continue

            dns_listener = MultiListener(socket.SOCK_DGRAM)

            if listenip_v6:
                lv6 = (listenip_v6[0], port)
                dnsport_v6 = port
            else:
                lv6 = None
                dnsport_v6 = 0

            if listenip_v4:

def send(self, dstip, data):
        debug2('UDP: sending to %r port %d\n' % dstip)
        try:
            self.sock.sendto(data, dstip)
        except socket.error:
            _, e = sys.exc_info()[:2]
            log('UDP send to %r port %d: %s\n' % (dstip[0], dstip[1], e))
            return