public RipenessSorter get_category(string name){
if (!categories.ContainsKey (name))
categories [name] = new RipenessSorter ();
return categories [name];
}
public RipenessSorter copy_from(RipenessSorter that){
rx_berries.SetRange (that.all_berries.Select (score => score.copy_of ()));
return this;
}