Check if token non-selection was triggered

app.py

@@ -1249,7 +1249,7 @@ Any framework based on `llama-cpp-python` will let you select which chat templat
         choice: int,
         indices: list[int],
     ):
-        if choice < 0 or choice >= len(indices) or (token := indices[choice]) < 0:
+        if choice is None or choice < 0 or choice >= len(indices) or (token := indices[choice]) < 0:
             raise gr.Error('Token not found')
 
         return {