diff --git a/python/sdist/amici/petab/petab_import.py b/python/sdist/amici/petab/petab_import.py
index 902bf837ef..cb896b39e3 100644
--- a/python/sdist/amici/petab/petab_import.py
+++ b/python/sdist/amici/petab/petab_import.py
@@ -10,6 +10,7 @@
 import shutil
 from pathlib import Path
 from typing import Union
+from warnings import warn
 
 import amici
 import petab