func FilterSelects(lbls map[string]string) FetchOption {
	return func(h *dependency) {
		h.filter.selects = lbls
	}
}

// FilterIndex selects only objects matching a key in an index.
func FilterIndex[I any, K comparable](idx *Index[I, K], k K) FetchOption {
	return func(h *dependency) {
		// Index is used to pre-filter on the List, and also to match in Matches. Provide type-erased methods for both