def keys
import bend-toon-codec@0.1.0.0/src/fold.bend as Foldimport Base
import bend-toon-codec@0.1.0.0/src/json.bend as J
52def keys(+fs: J.Json) -> List<&2, String>:
53 match fs:
54 case J.JField{k, v, t}:
55 Con{k, keys(t)}
56 case _:
57 Nil{}