public static void main(String[] args) {

    System.out.println("Dataset cleanup migration");

    // set your MongoDB Cluster connection string
    // TODO> Ticket: Migration - set the cluster connection string.
    String mongoUri = "mongodb+srv://m220student:m220password@mflix-cpo7t.mongodb.net/test?retryWrites=true";

    // instantiate database and collection objects
    MongoDatabase mflix = MongoClients.create(mongoUri).getDatabase("mflix");
    MongoCollection<Document> movies = mflix.getCollection("movies");
    Bson dateStringFilter = type("lastupdated", "string");
    String datePattern = "yyyy-MM-dd HH:mm:ss";
    // TODO> Ticket: Migration - create a query filter that finds all
    // documents that are required to be updated and the correct date
    // format pattern
    Bson queryFilter = new Document("lastupdated",new Document("$type",BsonType.STRING));
    SimpleDateFormat dateFormat = new SimpleDateFormat(datePattern);

    // create list of bulkWrites to be applied.
    List<WriteModel<Document>> bulkWrites = new ArrayList<>();

    // iterate over the documents and apply the transformations.
    for (Document doc : movies.find(dateStringFilter)) {

      // Apply lastupdate string to date conversion
      WriteModel<Document> updateDate = transformDates(doc, dateFormat);
      if (updateDate != null) {
        bulkWrites.add(updateDate);
      }
    }

    // TODO> Ticket: Migration - create a query filter that finds
    // documents where `imdb.rating` is of type string

    Bson ratingStringFilter = type("imdb.rating", "string");
    for (Document doc : movies.find(ratingStringFilter)) {
      // Apply "imdb.rating" string to number conversion
      WriteModel<Document> updateRating = transformRating(doc);
      if (updateRating != null) {
        bulkWrites.add(updateRating);
      }
    }

    // execute the bulk update
    // TODO> Ticket: Migration - set the bulkWrite options
    BulkWriteOptions bulkWriteOptions = new BulkWriteOptions().ordered(false);
    if (bulkWrites.isEmpty()) {
      System.out.println("Nothing to update!");
      System.exit(0);
    }

    BulkWriteResult bulkResult = movies.bulkWrite(bulkWrites, bulkWriteOptions);
    // output the number of updated documents
    System.out.println(
        MessageFormat.format("Updated {0} documents", bulkResult.getModifiedCount()));
  }