change memory to window

chain.py

@@ -42,8 +42,8 @@ def get_chain():
     """
 
     prompt = PromptTemplate(input_variables=["chat_history", "query", "context"], template=template)
-    memory = ConversationBufferMemory(memory_key="chat_history", input_key="query")
-    chat = ChatOpenAI(temperature=0, streaming=True, max_token=400)
+    memory = ConversationBufferWindowMemory(memory_key="chat_history", input_key="query", k=6)
+    chat = ChatOpenAI(temperature=0, streaming=True)
 
     chain = load_qa_chain(llm=chat, chain_type="stuff", memory=memory, prompt=prompt)