Update app.py

app.py

@@ -6,8 +6,8 @@ from PyPDF2 import PdfReader
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain_community.embeddings.huggingface import HuggingFaceEmbeddings
 from langchain.vectorstores import chroma
-from langchain.chains.retrieval_qa.base import RetrievalQA
-#from langchain.chains.question_answering import load_qa_chain
+#from langchain.chains.retrieval_qa.base import RetrievalQA
+from langchain.chains.question_answering import load_qa_chain
 from langchain_community.llms import huggingface_hub
 from langchain.document_loaders.pdf import PyMuPDFLoader 
 #from transformers import AutoTokenizer, AutoModelForCausalLM
@@ -68,12 +68,12 @@ def main():
             llm = huggingface_hub.HuggingFaceHub(repo_id="google/flan-t5-small",
                                                   model_kwargs={"temperature":1.0, "max_length":256})
             docs = vector_store.similarity_search(query=query, k=3)
-            global chain
-            #chain = load_qa_chain(llm=llm, chain_type="stuff")
-            #response = chain.run(input_documents=docs, question=query)
-            retriever=vector_store.as_retriever()
-            chain = RetrievalQA.from_chain_type(llm=llm,chain_type="stuff",retriever=retriever)
-            response = chain.run(chain)
+           
+            chain = load_qa_chain(llm=llm, chain_type="stuff")
+            response = chain.run(input_documents=docs, question=query)
+            #retriever=vector_store.as_retriever()
+            #chain = RetrievalQA.from_chain_type(llm=llm,chain_type="stuff",retriever=retriever)
+            #response = chain.run(chain)
             st.write(response)