diff --git a/fink_science/rubin/cats/processor.py b/fink_science/rubin/cats/processor.py
index 81b692a9..7e1bdeed 100644
--- a/fink_science/rubin/cats/processor.py
+++ b/fink_science/rubin/cats/processor.py
@@ -94,6 +94,10 @@ def predict_nn(
     >>> df.filter(df['argmax'] == 0).count()
     50
     """
+    import os
+
+    os.environ["TF_USE_LEGACY_KERAS"] = "1"
+
     import tensorflow as tf
     from tensorflow import keras
 
diff --git a/fink_science/ztf/hostless_detection/processor.py b/fink_science/ztf/hostless_detection/processor.py
index bcae7495..dec12e7a 100644
--- a/fink_science/ztf/hostless_detection/processor.py
+++ b/fink_science/ztf/hostless_detection/processor.py
@@ -229,9 +229,17 @@ def run_potential_hostless(
                         science_stamp, template_stamp
                     )
                 )
-                kstest_results.append([kstest_science, kstest_template, is_processed_true])
+                kstest_results.append([
+                    kstest_science,
+                    kstest_template,
+                    is_processed_true,
+                ])
             else:
-                kstest_results.append([default_result, default_result, is_processed_false])
+                kstest_results.append([
+                    default_result,
+                    default_result,
+                    is_processed_false,
+                ])
         else:
             kstest_results.append([default_result, default_result, is_processed_false])
     return pd.Series(kstest_results)