diff --git a/src/flownet/prediction/_run_pred.py b/src/flownet/prediction/_run_pred.py
index 6063dd5d2..d4e4a85d9 100644
--- a/src/flownet/prediction/_run_pred.py
+++ b/src/flownet/prediction/_run_pred.py
@@ -25,7 +25,7 @@ def _run_ert(output_folder: pathlib.Path) -> None:
 
     """
     subprocess.run(
-        f"ert ensemble_experiment pred_config.ert",
+        "ert ensemble_experiment pred_config.ert",
         cwd=output_folder,
         shell=True,
         check=True,