presto-google-sheets/src/main/java/io/prestosql/plugin/google/sheets/SheetsClient.java/SheetsClient/getSheetExpressionForTable
class SheetsClient:    private Optional<String> getSheetExpressionForTable(String tableName)
    {
        Map<String, Optional<String>> tableSheetMap = getAllTableSheetExpressionMapping();
        if (!tableSheetMap.containsKey(tableName)) {
            return Optional.empty();
        }
        return tableSheetMap.get(tableName);
    }