[Bug] ModuleNotFoundError: No module named 'causalrag.retriever.base' when running example code

[EternityJune25]

Module Import Error when Running CausalRAG Example

Issue Description

When trying to run the example code from CausalRAG, I encountered a module import error. The error occurs in the import chain when trying to import the CausalRAGPipeline.

Error Message

$ python examples/basic_usage.py
Traceback (most recent call last):
File "examples/basic_usage.py", line 15, in
from causalrag import CausalRAGPipeline
File "causalrag/init.py", line 16, in
from .pipeline import CausalRAGPipeline
File "causalrag/pipeline.py", line 7, in
from .retriever.vector_store import VectorStoreRetriever
File "causalrag/retriever/init.py", line 10, in
from .bm25_retriever import BM25Retriever
File "causalrag/retriever/bm25_retriever.py", line 10, in
from .base import BaseRetriever
ModuleNotFoundError: No module named 'causalrag.retriever.base'