updated import statements

app.py

@@ -1,9 +1,9 @@
 import gradio as gr
 from transformers import pipeline
-from langchain.llms import OpenAI
+from langchain_community.llms import OpenAI
 from langchain.chains import LLMChain
 from langchain.prompts import PromptTemplate
-from langchain.document_loaders import PyPDFLoader
+from langchain_community.document_loaders import PyPDFLoader
 
 def load_document(file_path):
     """Loads a PDF document and returns its content."""