Wax Beans

1 3 oz can wax beans 1 can green beans 1 can red kidney beans 1 small onion sliced thin 1/2 green pepper chopped Dressing 2/3 cup sugar 2/3 cup vinegar 1/3 cup salad oil 1 teaspoon salt 1/2 teaspoon celery seed 1/3 teaspoon black pepper