diff --git a/docs/notebooks/exercises/CombineModels.ipynb b/docs/notebooks/exercises/CombineModels.ipynb
index 7fd4ebf6bba146d550552ccc04e980f3b52ee094..71ae53eba56b9ce74c5afc86132d96c4aab34d91 100644
--- a/docs/notebooks/exercises/CombineModels.ipynb
+++ b/docs/notebooks/exercises/CombineModels.ipynb
@@ -48,7 +48,8 @@
                 "from py_wake.superposition_models import *\n",
                 "from py_wake.deflection_models import *\n",
                 "from py_wake.turbulence_models import *\n",
-                "from py_wake.ground_models import *"
+                "from py_wake.ground_models import *\n",
+                "from py_wake.deficit_models.utils import *"
             ]
         },
         {