help! about pypcap.dispatch

[doit4um at gmail.com]

Hi,
 
   I'm using Python 2.7.6 in Centos 6.5. 
   
   I have defined  
   "p = pcap.pcap(timeout_ms=1000)
    def function(timestamp,pkt,*args):
   "
   and try to run "p.dispatch(-1,function)"

   and I got this:
   p.dispatch(-1,function)
   File "pcap.pyx", line 296, in pcap.pcap.dispatch (pcap.c:3182)
  TypeError: raise: exception class must be a subclass of BaseException

   why this happened? Anybody know how to solve it?

   thanks!