anchor.diff:  
     void transactions_batchedWrites() {
       // [START transactions_batched_writes]
  -    /*
  -
  -
  -
  -
  -
  -
  -// Commit the batch
  -batch.commit().then(() => {
  -    // ...
  -});
  -   */
       // Get a new write batch
       final batch = db.batch();
   
  
positive.code: 
    void performSimpleAndCompoundQueries_exampleData() {
      // [START perform_simple_and_compound_queries_example_data]
      /*
  
     */
      final cities = db.collection("cities");
      final data1 = <String, dynamic>{
        "name": "San Francisco",
  
negative.code: 
    void performSimpleAndCompoundQueries_queryOperators() {
      // [START perform_simple_and_compound_queries_query_operators]
      final citiesRef = db.collection("cities");
      final stateQuery = citiesRef.where("state", isEqualTo: "CA");
      final populationQuery = citiesRef.where("population", isLessThan: 100000);
  