The OnDiskInvertedLists merge_from takes several other InvertedLists as input

https://github.com/facebookresearch/faiss/blob/main/faiss/invlists/OnDiskInvertedLists.h#L104

while the default merge_from from InvertedLists does take a single one

https://github.com/facebookresearch/faiss/blob/main/faiss/invlists/InvertedLists.h#L112

this is inconsistent and the OnDisk one does not have an option to shift indices.