diff --git a/scripts/nightly.yaml b/scripts/nightly.yaml
index 81f084b3b..2ff044cd7 100644
--- a/scripts/nightly.yaml
+++ b/scripts/nightly.yaml
@@ -58,7 +58,7 @@ stages:
         cd doc
         python mk_api_doc.py --z3py-package-path=../build/python/z3
         eval `opam config env` 
-        ocamldoc -html -d api/html/ml -sort -hide Z3 -I +zarith -I ../build/api/ml ../build/api/ml/z3enums.mli ../build/api/ml/z3.mli
+        ocamldoc -html -d api/html/ml -sort -hide Z3 -I $( ocamlfind query zarith ) -I ../build/api/ml ../build/api/ml/z3enums.mli ../build/api/ml/z3.mli
         cd ..
     - script: zip -r api.zip doc/api
     - script: cp api.zip $(Build.ArtifactStagingDirectory)/.