supermarket = { "milk": {"quantity": 20, "price": 1.19},
"biscuits": {"quantity": 32, "price": 1.45},
"butter": {"quantity": 20, "price": 2.29},
"cheese": {"quantity": 15, "price": 1.90},
"bread": {"quantity": 15, "price": 2.59},
"cookies": {"quantity": 20, "price": 4.99},
"yogurt": {"quantity": 18, "price": 3.65},
"apples": {"quantity": 35, "price": 3.15},
"oranges": {"quantity": 40, "price": 0.99},
"bananas": {"quantity": 23, "price": 1.29}}
customers = ["Frank", "Mary", "Paul"]
shopping_lists = {"Frank" : [('milk', 5), ('apples', 5),
('butter', 1), ('cookies', 1)],
"Mary": [('apples', 2), ('cheese', 4),
('bread', 2), ('pears', 3),
('bananas', 4), ('oranges', 1),
('cherries', 4)],
"Paul": [('biscuits', 2), ('apples', 3),
('yogurt', 2), ('pears', 1),
('butter', 3), ('cheese', 1),
('milk', 1), ('cookies', 4)]}