diff --git a/optillm/cepo/cepo.py b/optillm/cepo/cepo.py
index c6e8a362..f58d2694 100644
--- a/optillm/cepo/cepo.py
+++ b/optillm/cepo/cepo.py
@@ -254,6 +254,7 @@ def generate_n_completions(system_prompt: str, initial_query: str, client: Any,
     cb_log["system_prompt"] = system_prompt
     cb_log["initial_query"] = initial_query
     completions = []
+    approaches = None
 
     # Generate Approach and Descriptions
     if cepo_config.use_plan_diversity:
diff --git a/optillm/cepo/configs/cepo_config.yaml b/optillm/cepo/configs/cepo_config.yaml
index 9c843372..27da0da5 100644
--- a/optillm/cepo/configs/cepo_config.yaml
+++ b/optillm/cepo/configs/cepo_config.yaml
@@ -13,5 +13,5 @@ planning_max_tokens_step2: 4096
 planning_max_tokens_step3: 4096
 planning_max_tokens_step4: 4096
 use_plan_diversity: False
-rating_model: None
+rating_model: null
 print_output: False
\ No newline at end of file