Besides loading from JSON and dicts, it could be useful to have an easy way to load a set of feature flags from - [dynaconf](https://www.dynaconf.com/) which is widely used for configuration, and uses a [dict-like](https://www.dynaconf.com/#reading-settings-variables) interface - [pydantic-settings](https://docs.pydantic.dev/latest/usage/pydantic_settings/) that FastAPI seems to [endorse](https://fastapi.tiangolo.com/advanced/settings/#pydantic-settings) as well, though I see it less in practice This could expand the usage of this module, and would make it easier to integrate it.