Function validation does not validate output cardinality

[hugohills-regnosys]

Function validation does not validate output cardinality:

type Foo:
    attr boolean (1..1)

func ShouldEvalulateToOptionalSingleCardinality:
    inputs:
        foos Foo (0..*)
    output:
        result boolean (1..1) // validation on cardinality - if empty list of foos provided, then result will be empty

    set result:
        foos 
            extract item -> attr
            then all = True