1namespace momoney.database.transactions
 2{
 3    public interface IContext
 4    {
 5        bool contains<T>(IKey<T> key);
 6        void add<T>(IKey<T> key, T value);
 7        T value_for<T>(IKey<T> key);
 8        void remove<T>(IKey<T> key);
 9    }
10}