Cannot assign new keys to hparams of type dict

[thelostscout]

Code example:

from lightning_trainable.hparams import HParams, AttributeDict

class TestHParams(HParams):
    d: dict

    @classmethod
    def validate_parameters(cls, hparams: AttributeDict) -> AttributeDict:
        print(hparams.d)
        hparams.d["key"] = 1
        print(hparams.d)
        return super().validate_parameters(hparams)

hparams = TestHParams(d=dict())
print(hparams)

Expected: d == {"key": 1} Actual: d == {}