Update app.py

app.py

@@ -12,11 +12,12 @@ genai.configure(api_key="AIzaSyD2o8vjePJb6z8vT_PVe82lVWMD3_cBL0g")
 def predict(message :str ,history : Optional[List],topic : Optional[str] = "OIC") -> str:
     model = genai.GenerativeModel("gemini-pro")
     his = []
-    for i,j in history:
-        his.extend([
-            {"role": "user", "parts": i},
-            {"role": "model", "parts": j},
-        ])
+    if history:
+        for i,j in history:
+            his.extend([
+                {"role": "user", "parts": i},
+                {"role": "model", "parts": j},
+            ])
     chat = model.start_chat(
         history=his
     )