почему setCellValueEx красный?

package com.javarush.games.snake;
import com.javarush.engine.cell.*;



public class Apple extends GameObject {
    private final String APPLE_SIGN = "\uD83C\uDF4E";
    public Apple(int x, int y) {
        super(x, y);
    }

    public void draw(Game game) {
        setCellValueEx (x, y, Color.NONE, APPLE_SIGN,Color.GREEN, 75);
    }
}