Domain exceptions

The domain defines a focused validation exception for key-derived sets:

Exception	Raised when	Typical use
EmptySetGeneratedFromKeysError	Filtering falsy values from an iterable leaves no keys.	Domain helper code rejects an empty result rather than continuing with an unusable set.

The current use is in str_iterable_as_set_without_null_values, which normalizes and validates a collection of string keys. This exception belongs to the domain base package; exceptions in the shared layer or in adapters are separate and are not domain exceptions.

See domain base for shared domain ownership and the generated API reference for the exact exception definition.