Paint a heartwarming scene reminiscent of a whimsical children's book illustration. Picture a majestic black shepherd/lab breed dog proudly standing beside a charming white house, complete with a spacious wooden deck. Through the window, capture the image of a contented man, cheerfully whistling and gazing outside. Embrace a delightful watercolor style, filled with vibrant colors and gentle brushstrokes. The overall composition should exude warmth and happiness, transporting viewers to a world o