Function is_placeholder

crates/vm/src/stdlib/_functools.rs:118–120

(obj: &PyObjectRef)

    }

    fn is_placeholder(obj: &PyObjectRef) -> bool {
        &*obj.class().name() == "_PlaceholderType"
    }

    fn count_placeholders(args: &[PyObjectRef]) -> usize {
        args.iter().filter(|a| is_placeholder(a)).count()