code: function (id) {
      if (!id || !_.isString(id)) {
        var err = new Error('Please pass a valid string as id!');
        debug(err);
        throw err;
      }
  
      return new AggregateModel(id, this.modelInitValues);
    }
docs: Returns a new aggregate model, to be used in the command and event functions.
  @param {String} id The aggregate id.
  @returns {AggregateModel}