[Feature]: Support len(processing_module) to get number of items

[rly]

What would you like to see added to PyNWB?

A ProcessingModule is a special MultiContainerInterface that contains a labeled dictionary of NWBDataInterface objects called data_interfaces. It also has a description but nothing else. It's a bit unwieldy to call len(nwbfile.processing["behavior"].data_interfaces). It would be nicer to treat nwbfile.processing["behavior"] as a dictionary and be able to call len and other functions on it: len(nwbfile.processing["behavior"]).

For convenience, getitem works, e.g., nwbfile.processing["behavior"]["child1"], and I believe iterating works.

It might also be nice to move the other dictionary functions up to that level, e.g., keys, values, items.

Is your feature request related to a problem?

No response

What solution would you like?

See above.

Do you have any interest in helping implement the feature?

Yes.

Code of Conduct

• I agree to follow this project's Code of Conduct
• Have you checked the Contributing document?
• Have you ensured this change was not already requested?

[h-mayorquin]

I think this would make interacting with the API easier. +1 on moving all the dictionary machine directly to the object itself instead of within data_interfaces.

[bendichter]

I like it.

The best counter-argument I can think of would be what if ProcessingModule gets extended is a way where these operations are ambiguous, e.g. if someone added some kind of list or dict like internal object where len would be a sensible operation. I don't think that's likely to happen, though. I don't think I have ever seen an extension of ProcessingModule, and if it were to happen I would guess it would be to add attributes-like metadata, not container-like data.