import streamlit as st from dotenv import load_dotenv from PyPDF2 import PdfReader from langchain.text_splitter import CharacterTextSplitter from langchain.embeddings import HuggingFaceInstructEmbeddings from langchain.vectorstores import FAISS from langchain.memory import ConversationBufferMemory from langchain.chains.conversational_retrieval.base import ConversationalRetrievalChain from langchain.llms.huggingface_hub import HuggingFaceHub css = '''