P operated a department store within the city limits of Phoenix under the trade name Diamonds. As part of its business, P entered into agreements with other retailers to maintain certain departments within its stores. For this space, these special retailers pay P a percentage of gross receipts with a minimum monthly payment designated. The agreements are for a definite term and P may terminate at any time if the retailer is in default. The City of Phoenix (D) assessed a one percent privilege tax against the revenue generated by P's retailer agreements. P paid under protest and disputed the tax but lost the administrative hearing. P then sued D in Superior Court. The trial court granted P's summary judgment motion. D appealed.