Update app.py

app.py

@@ -11,6 +11,7 @@ from langchain.chains import ConversationalRetrievalChain
 from htmlTemplates import css, bot_template, user_template
 from langchain.llms import HuggingFaceHub, LlamaCpp, CTransformers  # For loading transformer models.
 from langchain.document_loaders import PyPDFLoader, TextLoader, JSONLoader, CSVLoader
+from io import TextIOWrapper
 import tempfile # 임시 파일을 생성하기 위한 라이브러리입니다.
 import os