presto-google-sheets/src/main/java/io/prestosql/plugin/google/sheets/SheetsMetadata.java/SheetsMetadata/listTables
class SheetsMetadata:    @Override
    public List<SchemaTableName> listTables(ConnectorSession session, Optional<String> schemaName)
    {
        if (!schemaName.isPresent()) {
            throw new PrestoException(SHEETS_UNKNOWN_SCHEMA_ERROR, "Schema not present - " + schemaName);
        }
        Set<String> tables = sheetsClient.getTableNames();
        List<SchemaTableName> schemaTableNames = new ArrayList<>();
        tables.forEach(t -> schemaTableNames.add(new SchemaTableName(schemaName.get(), t)));
        return schemaTableNames;
    }