docs: protected static double getPriority(List<CmsProperty> properties) {
  
          CmsProperty prop = CmsProperty.get(CmsPropertyDefinition.PROPERTY_XMLSITEMAP_PRIORITY, properties);
          if (prop.isNullProperty()) {
              return -1.0;
          }
          try {
              double result = Double.parseDouble(prop.getValue().trim());
              return result;
          } catch (NumberFormatException e) {
              return -1.0;
          }
      }