Brain hparams can only be accessed with dot notation, not by name #2898

Describe the bug

hparams from load_hyperpyyaml returns a Python dict, yet internally Brain converts it into a SimpleNamespace, which only allows attributes to be accessed via dot notation and no longer from their names.

When trying to access Brain.hparams by name, you get the following exception: TypeError: 'types.SimpleNamespace' object is not subscriptable

This makes scripting access to hparams -- in particular for parameter transfer applications -- a bit annoying and not at all idiomatic.

Expected behaviour

The described behaviour is unintuitive since I expected to be able to access the parameters in the same way as the hparams I passed originally, that is, by name.

So I would expect

import speechbrain as sb

model = sb.Brain(...)
assert model.hparams["foo"] is model.hparams.foo

To Reproduce

model = EncoderDecoderASR.from_hparams(source="speechbrain/asr-crdnn-rnnlm-librispeech")
model.hparams["asr"]

Environment Details

Python==3.10.16
speechbrain==1.0.3

(other environment details shouldn't be relevant)

Relevant Log Output

Additional Context

An obvious workaround is using getattr (in my example, getattr(model, "asr"). I'm raising the issue mainly as a feature request for native support, but understand if it's not a use case you'd like to support.