static double extractExtensionOrdinal(Object obj) {
        if (obj instanceof Attribute<?, ?>) {
            return extractExtensionOrdinal((Attribute<?, ?>) obj);
        } else {
            return extractExtensionOrdinal(obj.getClass());
        }
    }
Describe Structure of the attributes, as required by the schema.
@param instance
     Object whose attributes will be described.
@param context
     Fully configured Jenkins object used as the starting point for this configuration.
@since 1.35
@return CNode describing the attributes.
plugin/src/main/java/io/jenkins/plugins/casc/Configurator.java