[pox-dev] softwareswitch can't work

[Guangvy]

Hi ,
   Can you help me about this issue, it use the newest version:
 root@ubuntu:~/pox#
root@ubuntu:~/pox# 
root@ubuntu:~/pox# 
root@ubuntu:~/pox# 
root@ubuntu:~/pox# ./pox.py --no-openflow datapaths:softwareswitch 
--address=3.3.3.3
POX 0.2.0 (carp) / Copyright 2011-2013 James McCauley, et al.
Traceback (most recent call last):
  File "/root/pox/pox/boot.py", line 504, in boot
    if _do_launch(argv):
  File "/root/pox/pox/boot.py", line 235, in _do_launch
    if f(**params) is False:
  File "/root/pox/pox/datapaths/__init__.py", line 120, in softwareswitch
    extra_args = extra)
  File "/root/pox/pox/datapaths/__init__.py", line 84, in do_launch
    switch = cls(dpid=dpid, name="sw"+str(dpid), **kw)
  File "/root/pox/pox/datapaths/switch.py", line 1052, in __init__
    super(ExpireMixin,self).__init__(*args, **kw)
  File "/root/pox/pox/datapaths/switch.py", line 79, in __init__
    ports = [self.generate_port(i, dpid) for i in range(1, ports+1)]
  File "/root/pox/pox/datapaths/switch.py", line 183, in generate_port
    dpid = self.dpid
AttributeError: 'ExpiringSwitch' object has no attribute 'dpid'
root@ubuntu:~/pox# 
root@ubuntu:~/pox#