diff --git a/requirements_pinned.txt b/requirements_pinned.txt
--- a/requirements_pinned.txt
+++ b/requirements_pinned.txt
@@ -24,3 +24,4 @@ tempita==0.5.2
 testpath==0.4.4
 transaction==2.4.0
 vine==1.3.0
+wcwidth==0.1.7