@Nullable
    @NlsSafe
    private static String getSpecificExtensionAttribute(@NotNull Extension e,
                                                        @NotNull PsiClass parentBeanClass,
                                                        @NotNull @NonNls String attribute) {
      ExtensionPoint ep = e.getExtensionPoint();
      if (ep == null) {
        return null;
      }
      PsiClass beanClass = ep.getBeanClass().getValue();
      if (beanClass == null) {
        return null;
      }
      if (!InheritanceUtil.isInheritorOrSelf(beanClass, parentBeanClass, true)) {
        return null;
      }

      DomAttributeChildDescription attributeDescription = e.getGenericInfo().getAttributeChildDescription(attribute);
      if (attributeDescription == null) {
        return null;
      }
      return attributeDescription.getDomAttributeValue(e).getStringValue();
    }
@Nullable
    @NlsSafe
    private static String getSpecificExtensionAttribute(@NotNull Extension e,
                                                        @NotNull PsiClass parentBeanClass,
                                                        @NotNull @NonNls String attribute)