python3.8 one line statement

in a dictionary whose keys are the warehouses: associated with each warehouse is an inner dictionary whose keys are the stocked products (and whose associated values are the inventory of that product in the warehouse). The inventory must always be a non-negative value; an inventory of 0 is legal. For example, a simple/small database might be.

db = {'Irvine' : {'brush': 3, 'comb': 2, 'wallet': 2}, 'Newport': {'comb': 7, 'stapler': 0}, 'Tustin' : {'keychain': 3, 'pencil': 4, 'wallet': 3}}

This data structure means that

1. The Irvine warehouse stocks 3 brushes, 2 combs, and 2 wallets.

2. The Newport warehouse stocks 7 combs, and 0 staplers.

3. The Tustin warehouse stocks 3 keychains, 4 pencils, and 3 wallets.

(a) The by_product_inventory_count function returns a list of str (warehouse names), sorted ascending by which warehouses have the largest number of products. If two warehouses store the same number of products, they should appear in ascending order of warehouse name: for the db dictionary above the result is ['Newport', 'Irvine', 'Tustin'].