[BUG] Cannot query across multiple indexes

[Changle-ChangSu]

BUG Description
In the notebooks/2-Advanced_Getting_Started.ipynb, Query/Global Search section, where a comment says "pass in a single index name as a string or to query across multiple indexes, set index_name=[myindex1, myindex2]". However, when I try to set the index_name=["index1", "index2"], an error is raised:

Unprocessable Entity
b'{"detail":[{"type":"string_type","loc":["body","index_name"],"msg":"Input should be a valid string","input":["index1","index2"]}]}'

Seems that GraphRAG cannot support multi-graph search?

Or how can I solve this problem? This will be extremely helpful in business scenarios!