Fixed parallelism issue

app.py

@@ -13,7 +13,7 @@ def get_reply(response, username = None, histories = {}):
     history = histories.get(username, [])
     history.append(response)
     if response.endswith(("bye", "Bye", "bye.", "Bye.")):
-        history[username] = []
+        histories[username] = []
         return "<div class='chatbot'>Chatbot restarted</div>", histories
     if len(history) > 4: history = history[-4:]
     inputs = tokenizer("    ".join(history), return_tensors="pt")