WAI-ARIA group is missing a name

[mhk33]

We run our catalog through SiteImprove to check accessibility and get the following WCAG 2.0 Level A error:

A group created with the WAI-ARIA role="group" or role="radiogroup" is missing a name.
How to fix it: Use either the WAI-ARIA attribute 'aria-label' or 'aria-labelledby' to name the group.

It is referring to each use of this list in the blacklight-hierarchy gem:

<ul role="group" style="display: none;">

It looks like the

needs the aria-label or aria-labelledny attribute.