In exercises/18_iterators/iterators5.rs I cant resolve the test for count_collection_iterator

[sgtnasty]

I am up to iterators5.rs and got the first function completed (count_iterator) solved, but I am having trouble with the second function called count_collection_iterator. As I understand it, I need to use the fold method, but I am unclear how to use it. Specifically how to match it with the value: Progress that is passed in.

fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
    let init: usize = 0;
    collection.iter().fold(init, |mut acc: usize, item: &HashMap<String, Progress>| {
        acc += 1;
        acc
    })
}