pybess: don't pass self to BESS.attach_module() (#521)

Author: melvinw

pybess/bess.py

@@ -521,7 +521,7 @@ def attach_task(self, module_name, parent='', wid=-1,
 
     # Deprecated alias for attach_task
     def attach_module(self, *args, **kwargs):
-        return self.attach_task(self, *args, **kwargs)
+        return self.attach_task(*args, **kwargs)
 
     def get_tc_stats(self, name):
         request = bess_msg.GetTcStatsRequest()