private Connection getConnectionWithMultiplyFunction()

      throws ClassNotFoundException, SQLException {

    Connection connection =

        DriverManager.getConnection("jdbc:calcite:");

    CalciteConnection calciteConnection =

        connection.unwrap(CalciteConnection.class);

    SchemaPlus rootSchema = calciteConnection.getRootSchema();

    SchemaPlus schema = rootSchema.add("s", new AbstractSchema());

    final TableFunction table =

        TableFunctionImpl.create(Smalls.MULTIPLICATION_TABLE_METHOD);

    schema.add("multiplication", table);

    return connection;

  }