Scirpy tutorial incorrect - working with multimodal data

[benemead]

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Hi There,

I find myself in the unfortunate position where I need to work with airr data within an anndata as opposed to it's own modality in a mudata - I was reading the tutorial documentation here, specifically implementing this code:

# Map each cell barcode to its respective numeric index (assumes obs_names are unique)
barcode2idx = {barcode: i for i, barcode in enumerate(adata_airr.obs_names)}
# Generate a slice for the awkward array that retrieves the corresponding row
# from `adata_airr` for each barcode in `adata_gex`. `-1` will generate all
# "None"s for barcodes that are not in `adata_airr`
idx = [barcode2idx.get(barcode, -1) for barcode in adata_gex.obs_names]
adata_gex.obsm["airr"] = adata_airr.obsm["airr"][idx]

This asserts that the index -1 will generate Nones but my reading (and in practice) is that it's just inserting the last record, which in fact is a valid record... am I missing something here? Guidance on in fact populating Nones would be very helpful!

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