code: public static Bson ascending(final List<String> fieldNames) {
          notNull("fieldNames", fieldNames);
          return orderBy(fieldNames, new BsonInt32(1));
      }
docs: Create a sort specification for an ascending sort on the given fields.
  
  @param fieldNames the field names, which must contain at least one
  @return the sort specification
  @mongodb.driver.manual reference/operator/meta/orderby Sort