Update app.py conditional error fix

app.py

@@ -69,30 +69,33 @@ def retry_query(
     lookback = 3,
     max_new_tokens = 256,
 ):
-
-    query = history[-1][0]
-    history[-1][1]  = None
-    
-    generateKwargs = dict(
-        max_new_tokens = max_new_tokens,
-        seed = 1337,
-    )
-    
-    formatted_query = format_prompt(query, history, lookback)
-    
-    stream = client.text_generation(
-        formatted_query,
-        **generateKwargs,
-        stream = True,
-        details = True,
-        return_full_text = False
-    )
-    
-    history[-1][1] = ""
+    if history == None:
+        pass
     
-    for response in stream:
-        history[-1][1] += response.token.text
-        yield history
+    else:
+        query = history[-1][0]
+        history[-1][1]  = None
+        
+        generateKwargs = dict(
+            max_new_tokens = max_new_tokens,
+            seed = 1337,
+        )
+        
+        formatted_query = format_prompt(query, history, lookback)
+        
+        stream = client.text_generation(
+            formatted_query,
+            **generateKwargs,
+            stream = True,
+            details = True,
+            return_full_text = False
+        )
+        
+        history[-1][1] = ""
+        
+        for response in stream:
+            history[-1][1] += response.token.text
+            yield history
 
         
 """