diff --git a/relational/relation.py b/relational/relation.py
index 8931db2..e3f163d 100644
--- a/relational/relation.py
+++ b/relational/relation.py
@@ -21,7 +21,7 @@
 # relational operations on them.
 
 import csv
-from itertools import chain
+from itertools import chain, repeat
 
 from relational.rtypes import *