is it possible to define a schema for semi-homogenous maps? I have a map with a specific (optional) key that needs to point at one schema for its value (when present) but then every other key in the map is of a different type whose values are all of yet another type. to make things extra fun, I need that optional key to go through a custom decoder fn. so the specific key's schema looks like:

[:and
 [:map-of ::at-context :any] ; for ::at-context's decode fn
 [:map ["@context" {:optional true} ::context]]]

[:map-of ::iri ::val]