code: function (cmd) {
      var aggregateId = dotty.get(cmd, this.definitions.command.aggregateId);
      var aggregateName = this.aggregate.name;
      var contextName = this.aggregate.context.name;
  
      var toLoad = [{
        context: contextName,
        aggregate: aggregateName,
        aggregateId: aggregateId
      }];
  
      if (_.isFunction(this.getStreamsInfo)) {
        toLoad = this.getStreamsInfo(cmd);
        if (!_.isArray(toLoad)) {
          toLoad = [toLoad];
        }
        toLoad.forEach(function (l) {
          l.aggregateId = l.aggregateId || aggregateId;
        });
      }
  
      if (toLoad[0].context !== contextName || toLoad[0].aggregate !== aggregateName) {
        throw new Error('First stream to load has to be the new one!');
      }
  
      return toLoad;
    }
docs: Get infos to load correct stream.
  @param {Object} cmd The command object.
  @returns {Array}