code: function (preLoadCond) {
      if (!preLoadCond || !_.isObject(preLoadCond)) {
        var err = new Error('Please inject a valid preCondition object!');
        debug(err);
        throw err;
      }
  
      if (!preLoadCond.payload) {
        preLoadCond.payload = this.aggregate.defaultPreLoadConditionPayload;
      }
  
      if (this.preLoadConditions.indexOf(preLoadCond) < 0) {
        preLoadCond.defineAggregate(this.aggregate);
        this.preLoadConditions.push(preLoadCond);
        this.preLoadConditions = _.sortBy(this.preLoadConditions, function(pc) {
          return pc.priority;
        });
      }
    }
docs: Injects the pre-load-condition function.
  @param {Function} preLoadCond The pre-load-condition function that should be injected