You can use spec to verify that "a value only contains items described in the spec". The core library doesn't make it easy, but spell-spec [1] contains some use

You can use spec to verify that "a value only contains items described in the spec". The core library doesn't make it easy, but spell-spec [1] contains some useful helpers. [1] https://github.com/bhauman/spell-spec https://github.com/bhauman/spell-spec