Removed basecallBack code

pipeline.py

@@ -27,7 +27,7 @@ from langchain.chains import RetrievalQA, LLMChain
 from langchain.prompts import PromptTemplate
 from langchain.docstore.document import Document
 
-from langchain.callbacks.base import BaseCallbacks  # Updated import
+# from langchain.callbacks.base import BaseCallbacks  # Updated import
 # from langchain.callbacks.manager import CallbackManager
 from langchain.callbacks import StdOutCallbackHandler
 # Custom chain imports