added reset feature

app.py

@@ -67,6 +67,9 @@ def predict(message, history):
             item = (element[0] or "", element[1] or "")
             chat_history.append(item)
 
+    if not chat_history:
+        qa_chain.reset()
+
     q = Queue()
     result = Queue()
     t = Thread(target=task, args=(message, chat_history, q, result))

app_modules/llm_inference.py

@@ -28,6 +28,9 @@ class LLMInference(metaclass=abc.ABCMeta):
 
         return self.chain
 
+    def reset(self) -> None:
+        self.chain = None
+
     def run_chain(self, chain, inputs, callbacks: Optional[List] = []):
         result = chain.invoke(inputs, {"callbacks": callbacks})
         if "text" in result: