diff --git a/requirements-dev.txt b/requirements-dev.txt
index 4298010..2c97239 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -7,3 +7,5 @@ markdown>=2.6
 pytest
 pytest-randomly>=1.1
 pytest-cov
+# frappy mlz
+zapf >= 0.4.7