Update app.py

app.py

@@ -3,7 +3,7 @@ from langchain.vectorstores import Chroma
 from langchain.embeddings.openai import OpenAIEmbeddings
 from langchain.schema import Document
 from langchain.chat_models import ChatOpenAI
-from langchain.prompts.chat import ChatPromptTemplate
+from langchain.schema import SystemMessage, HumanMessage
 from PyPDF2 import PdfReader
 import os
 
@@ -54,15 +54,15 @@ def rag_from_pdf(question, pdf_file, api_key):
         # Initialize the LLM
         llm = ChatOpenAI(model="gpt-3.5-turbo")
         
-        # Create the chat prompt
+        # Create the chat messages
         messages = [
-            {"role": "system", "content": "You are a helpful assistant answering questions based on the provided PDF document."},
-            {"role": "user", "content": f"Question: {question}\n\nContext: {context}"}
+            SystemMessage(content="You are a helpful assistant answering questions based on the provided PDF document."),
+            HumanMessage(content=f"Question: {question}\n\nContext: {context}")
         ]
         
         # Generate response
         response = llm(messages=messages)
-        return response["choices"][0]["message"]["content"].strip()
+        return response.content.strip()
     except Exception as e:
         return f"An error occurred: {str(e)}"