presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/RaptorMetadata.java/RaptorMetadata/listViews
class RaptorMetadata:    @Override
    public List<SchemaTableName> listViews(ConnectorSession session, Optional<String> schemaName)
    {
        return dao.listViews(schemaName.orElse(null));
    }