code: function getRequired(element) {
          var elementRole = axs.utils.getRoles(element);
          if (!elementRole || !elementRole.applied)
              return [];
          var appliedRole = elementRole.applied;
          if (!appliedRole.valid)
              return [];
          return appliedRole.details['mustcontain'] || [];
      }
docs: Get a list of the roles this element must contain, if any, based on its ARIA role.
  @param {Element} element A DOM element.
  @return {Array.<string>} The roles this element must contain.