diff --git a/pyproject.toml b/pyproject.toml
index 13ea6df786..b1c4a6bdd6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,6 +41,7 @@ dependencies = [
     "casadi>=3.6.3",
     "xarray>=2022.6.0",
     "anytree>=2.8.0",
+    "typing-extensions",
 ]
 
 [project.urls]