public DailyGoodTree(MacroII model, int dailySupply, int minPrice, Market market) {
    super(model);
    Preconditions.checkArgument(minPrice >= 0);
    Preconditions.checkArgument(dailySupply > 0, "daily supply must be positive");
    this.minPrice = minPrice;
    this.market = market;
    this.dailySupply = dailySupply;
    market.registerSeller(this);

    startSteppables(model);
    name = market.getGoodType() + "Tree, price: " + minPrice;
  }