Update app.py

app.py

@@ -17,6 +17,7 @@ from langchain_community.document_loaders import PyPDFLoader
 from langchain_core.output_parsers import StrOutputParser
 from langchain_community.embeddings import HuggingFaceEmbeddings
 from langchain_community.llms import HuggingFaceHub
+from langchain_core.documents import Document  # Add this line
 
 huggingface_token = os.environ.get("HUGGINGFACE_TOKEN")