Update app.py

app.py

@@ -31,7 +31,7 @@ def models(text, model="Mixtral 8x7B"):
     for response in stream:
         if "Phi" in model:
             if output.endswith("<|assistant|>"):
-                output = output(-13)
+                output = output[:-13]
         else:      
             if not response.token.text == "</s>":
                 output += response.token.text