sim: remove unneeded import

diff --git a/migen/sim.py b/migen/sim.py
index ed40963dd3730bcc6c7179bad7da49a4bb8a6fc4..ed4399debc4756500555d3c30970f17dcd5a9ec9 100644 (file)
--- a/migen/sim.py
+++ b/migen/sim.py
@@ -1,5 +1,4 @@
 import operator
-from collections import defaultdict
 
 from migen.fhdl.structure import *
 from migen.fhdl.structure import _Operator, _Slice, _Assign, _Fragment