Add missing import; needed for tests to pass.

Author: mgree

pyretic/core/classifier.py

@@ -2,6 +2,7 @@
 # Classifiers
 # an intermediate representation for proactive compilation.
 
+
 class Rule(object):
     """
     A rule contains a filter and the parallel composition of zero or more
@@ -107,7 +108,7 @@ def __add__(self,c2):
     # Helper function for rshift: given a test b and an action p, return a test
     # b' such that p >> b == b' >> p.
     def _commute_test(self, act, pkts):
-        from pyretic.core.language import modify, drop, identity, Controller, CountBucket, DerivedPolicy
+        from pyretic.core.language import modify, drop, identity, Controller, CountBucket, DerivedPolicy, match
         while isinstance(act, DerivedPolicy):
             act = act.policy
         if act == identity: