Update app.py

app.py

@@ -73,6 +73,9 @@ def get_vectorstore(text_chunks):
 
 
 def get_conversation_chain(vectorstore):
+    if vectorstore is None:
+        return None
+        
     model_name_or_path = 'TheBloke/Llama-2-7B-chat-GGUF'
     model_basename = 'llama-2-7b-chat.Q2_K.gguf'
     model_path = hf_hub_download(repo_id=model_name_or_path, filename=model_basename)
@@ -85,6 +88,12 @@ def get_conversation_chain(vectorstore):
     memory = ConversationBufferMemory(
         memory_key='chat_history', return_messages=True)
     # 대화 검색 체인을 생성합니다.
+
+    retriever = vectorstore.as_retriever() if hasattr(vectorstore, 'as_retriever') else None
+    
+    if retriever is None:
+        return None
+        
     conversation_chain = ConversationalRetrievalChain.from_llm(
         llm=llm,
         retriever=vectorstore.as_retriever(),