Update app.py

app.py

@@ -17,7 +17,7 @@ from langchain.document_loaders import TextLoader
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain.embeddings import HuggingFaceEmbeddings
 from langchain.vectorstores import Chroma
-from langchain import HuggingFacePipeline
+from langchain.llms.huggingface_pipeline import HuggingFacePipeline
 from langchain.document_loaders import PyPDFDirectoryLoader
 from langchain.chains import ConversationalRetrievalChain
 from langchain.memory import ConversationBufferMemory