code: public <T> void put(TypeTag tag, T red, T black, T redCopy) {
          cache.put(tag, new Tuple<>(red, black, redCopy));
      }
docs: Adds a prefabricated value to the cache for the given type.
  
  @param tag A description of the type. Takes generics into account.
  @param red A "red" value for the given type.
  @param black A "black" value for the given type.
  @param redCopy A shallow copy of the given red value.