class PostgresqlOptions extends MysqlOptions {

    private PostgresqlOptions() {
        super();
    }

    private static volatile PostgresqlOptions instance;

    public static synchronized PostgresqlOptions instance() {<FILL_FUNCTION_BODY>}

    public static final ConfigOption<String> POSTGRESQL_CONNECT_DATABASE =
            new ConfigOption<>(
                    "jdbc.postgresql.connect_database",
                    "The database used to connect when init store, " +
                    "drop store or check store exist.",
                    disallowEmpty(),
                    "template1"
            );
}

        if (instance == null) {
            instance = new PostgresqlOptions();
            instance.registerOptions();
        }
        return instance;
    
<methods>public static synchronized org.apache.hugegraph.backend.store.mysql.MysqlOptions instance() <variables>public static final ConfigOption<java.lang.String> JDBC_DRIVER,public static final ConfigOption<java.lang.Boolean> JDBC_FORCED_AUTO_RECONNECT,public static final ConfigOption<java.lang.String> JDBC_PASSWORD,public static final ConfigOption<java.lang.Integer> JDBC_RECONNECT_INTERVAL,public static final ConfigOption<java.lang.Integer> JDBC_RECONNECT_MAX_TIMES,public static final ConfigOption<java.lang.String> JDBC_SSL_MODE,public static final ConfigOption<java.lang.String> JDBC_STORAGE_ENGINE,public static final ConfigOption<java.lang.String> JDBC_URL,public static final ConfigOption<java.lang.String> JDBC_USERNAME,private static volatile org.apache.hugegraph.backend.store.mysql.MysqlOptions instance