diff --git a/python/dune/perftool/loopy/symbolic.py b/python/dune/perftool/loopy/symbolic.py
index 131bed1c11c98bf51a12659fa507d3edc3eba778..7efae2d54331886f081fbf16102c6ddf77892763 100644
--- a/python/dune/perftool/loopy/symbolic.py
+++ b/python/dune/perftool/loopy/symbolic.py
@@ -7,6 +7,7 @@ from pymbolic.mapper.substitutor import make_subst_func
 
 import loopy as lp
 import pymbolic.primitives as prim
+from six.moves import intern
 
 
 #