Update utils.py

utils.py

@@ -57,7 +57,14 @@ def list_chat_histories():
 
 def load_chat_history(filename):
     """
-    Load a specific chat history file.
+    Load a specific chat history file with None check.
     """
-    with open(os.path.join("history", filename), "r") as f:
-        return json.load(f)
+    if not filename:
+        st.warning("No file selected to load history.")
+        return []
+    try:
+        with open(os.path.join("history", filename), "r") as f:
+            return json.load(f)
+    except FileNotFoundError:
+        st.warning("Selected history file not found.")
+        return []