Registry

Driver registries: config names to driver classes, plus the *IDN? patterns discovery matches against.

DriverEntry	A registered driver: its import path and the instrument identities that map to it.
IdnPattern	Which *IDN? replies a driver handles.
driver_registry	Return category's <CAT>_VENDOR_REGISTRY, or {} for a category without a config module.
iter_driver_entries	Yield (category, driver_name, entry) for every registered driver, in category order.
check_registry	Verify every pattern in registry can produce a valid config block for category.