System.err.println("Failed \"$get_capacity()\":");
System.err.println("Failed \"$get_capacity_count()\":");
    void update() {      Object o = get();      if (o == null) {        size = 0;        capacity = 0;        return;      }      // update capacity:      if (o instanceof Capacity) {        try {          capacity = ((Capacity) o).$get_capacity();        } catch (Exception e) {          System.err.println("Failed \"$get_capacity()\":");          e.printStackTrace();        }        if (maxCapacity < capacity) {          maxCapacity = capacity;        }      } else {        capacity = 0;      }      // update size:      if (o instanceof Size) {        try {          size = ((Size) o).$get_size();        } catch (Exception e) {          System.err.println("Failed \"$get_size()\":");          e.printStackTrace();        }      } else {        size = capacity;      }       if (maxSize < size) {        maxSize = size;      }    }