docs: private void refineAction(final Action action, final FilterKey key) {
          if (key.value != null && bindingMap != null && !bindingMap.isEmpty()) {
              final Map<String, Set<Element>> schemeMap = bindingMap.get(key.attribute);
              if (schemeMap != null && !schemeMap.isEmpty()) {
                  for (final Set<Element> submap: schemeMap.values()) {
                      for (final Element e: submap) {
                          final Element subRoot = searchForKey(e, key.value);
                          if (subRoot != null) {
                              insertAction(subRoot, key.attribute, action);
                          }
                      }
                  }
              }
          }
      }