My Mother’s Bean And Carrot Salad

Ingredients:1 small white onion, very thinly sliced2 tablespoons fresh parsley , snipped fineartificial sweetener , to taste (or 1/3 cup sugar)1 (16 ounce) can sliced carrots , drained1 teaspoon dry mustard1 (16 ounce) can green beans , drainedblack pepper1 teaspoon salt1 (16 ounce) can red kidney beans , rinsed and drained2 tablespoons salad oil1/4 cup