public function data_network_id_parameter() {
    return array(
      // Numeric values should always be accepted.
      array( 1, true ),
      array( '1', true ),
      array( 2, true ),

      // Null, false, and zero will be treated as the current network.
      array( null, true ),
      array( false, true ),
      array( 0, true ),
      array( '0', true ),

      // Other truthy or string values should be rejected.
      array( true, false ),
      array( 'string', false ),
    );
  }