Encountered a RecursionError: maximum recursion depth exceeded while running the rag_demo_a notebook, specifically in the graph_flow_merger.merge_documents function.

Steps to Reproduce:

• Run rag_demo_a(SAMPLE_DOCS) in the SRSWTIGraphFlow.ipynb notebook.
• The error occurs during the document merging step in SRSWTIGraphFlow.merge_documents(), which internally calls _build_hierarchical_graph().
• The recursion depth is exceeded, possibly due to an infinite loop or excessive recursive function calls in the graph-building logic.