def download_permissions
        can :download, String do |id|
          test_download(id)
        end

        can :download, SolrDocument do |obj|
          cache.put(obj.id, obj)
          test_download(obj.id)
        end
      end
def download_permissions
        can :download, String do |id|
          test_download(id)
        end

        can :download, SolrDocument do |obj|
          cache.put(obj.id, obj)
          test_download(obj.id)
        end
      end
This overrides hydra-head, (and restores the method from blacklight-access-controls)