public static GraphColoringLevel getLevelInstance(int levelNumber) {
		switch (levelNumber) {
			case 1:
				return generateLevelOne();
			case 2:
				return generateLevelTwo();
			case 3:
				return generateLevelThree();
			case 4:
				return generateLevelFour();
			case 5:
				return generateLevelFive();
			case 6:
				return generateLevelSix();
			case 7:
				return generateLevelSeven();
			case 8:
				return generateLevelEight();
			case 9:
				return generateLevelNine();
			default:
				return null;
		}
	}