to use lcel in refusal_chain.py

refusal_chain.py

@@ -1,20 +1,18 @@
 # refusal_chain.py
 import os
-from langchain.chains import LLMChain
+# from langchain.chains import LLMChain
 from langchain_groq import ChatGroq
-
+from langchain_core.output_parsers import StrOutputParser
 from prompts import refusal_prompt
 
 def get_refusal_chain() -> LLMChain:
     """
     Builds the refusal chain for out-of-scope queries.
     """
-    chat_groq_model = ChatGroq(
+        chat_groq_model = ChatGroq(
         model="Gemma2-9b-It",
-        groq_api_key=os.environ["GROQ_API_KEY"]
-    )
-    chain = LLMChain(
-        llm=chat_groq_model,
-        prompt=refusal_prompt
+        groq_api_key=os.environ["GROQ_API_KEY"]  # must be set in environment
     )
+    output_parser=StrOutputParser()
+    chain=refusal_prompt|chat_groq_model|output_parser
     return chain