diff --git a/src/mx_bluesky/bimorph_optimisation_plan/data_saver.py b/src/mx_bluesky/bimorph_optimisation_plan/data_saver.py
index 6a3dbbaea..0b0e6dbdf 100644
--- a/src/mx_bluesky/bimorph_optimisation_plan/data_saver.py
+++ b/src/mx_bluesky/bimorph_optimisation_plan/data_saver.py
@@ -43,7 +43,7 @@ def make_csv(docs: list) -> str:
 
     for doc in docs:
         if "run_start" in doc and "data_keys" in doc:
-            headers = [header for header in doc["data_keys"]]
+            headers = list(doc["data_keys"])
             headers.sort()
             for header in headers:
                 csv_dict[header] = []