code: function(db, date, callback) {
  
    // Check cache for services
    let cacheKey = db.id + "-" + date;
    let cache = cache_servicesDefaultByDate.get(cacheKey);
    if ( cache !== null ) {
      return callback(null, cache);
    }
  
    // Array of default services to return
    let rtn = [];
  
    // Get day of week
    let dt = DateTime.createFromDate(date);
    let dow = dt.getDateDOW();
  
    // Get default services
    let select = "SELECT service_id, monday, tuesday, wednesday, thursday, friday, " +
      "saturday, sunday, start_date, end_date FROM gtfs_calendar WHERE " + dow +
      "=" + Service.SERVICE_AVAILABLE + " AND start_date<=" + date + " AND " +
      "end_date>=" + date + ";";
  
    // Query the database
    db.select(select, function(err, results) {
  
      // Database Query Error
      if ( err ) {
        return callback(err);
      }
  
  
      // Parse each row in the results...
      for ( let i = 0; i < results.length; i++ ) {
        let row = results[i];
  
        let service = new Service(
          row.service_id,
          row.monday,
          row.tuesday,
          row.wednesday,
          row.thursday,
          row.friday,
          row.saturday,
          row.sunday,
          row.start_date,
          row.end_date
        );
  
        rtn.push(service);
      }
  
      // Add Services to Cache
      cache_servicesDefaultByDate.put(cacheKey, rtn);
  
      // Return the default services with provided callback
      return callback(null, rtn);
  
    });
  
  }
docs: Get the default Services in effect on the specified date.  These
  services don't include any changes due to service exceptions.
  
  @param {RightTrackDB} db The Right Track Database to query
  @param {int} date The date to query (yyyymmdd)
  @param {function} callback Callback function
  @param {Error} callback.error Database Query Error
  @param {Service[]} callback.services The selected Services