Update app.py

app.py

@@ -3,7 +3,7 @@ from langchain_huggingface import HuggingFaceEndpoint, HuggingFaceEmbeddings
 from langchain_text_splitters import RecursiveCharacterTextSplitter
 from langchain_community.vectorstores import Chroma
 from langchain_community.document_loaders import PyPDFLoader
-from langchain.chains import RetrievalQA
+from langchain.chains.retrieval_qa.base import RetrievalQA
 
 import gradio as gr
 import warnings
@@ -286,4 +286,4 @@ with gr.Blocks(title="QA Bot - PDF Question Answering") as demo:
 # Launch the app
 # ---------------------------
 if __name__ == "__main__":
-    demo.launch()
+    demo.launch()