REQUIRED_SCHEMA_NAME
if (nvlist_exists(schema, REQUIRED_SCHEMA_NAME))
if (nvlist_exists(schema, REQUIRED_SCHEMA_NAME)) {
if (!nvlist_exists_bool(schema, REQUIRED_SCHEMA_NAME))
if (dnvlist_get_bool(parameter, REQUIRED_SCHEMA_NAME, false))
if (dnvlist_get_bool(config, REQUIRED_SCHEMA_NAME, false)) {