Spotting an alleged discrepancy between the marketing claims Staples Inc. made about a $9.99 phone charger (the product was supposedly capable of providing 5,000 milliamps per hour and “Up to 2x Charges”) and the actual capacity of the device he purchased from a Staples store in Chicago (it could only pump out 3,400 mAh, which wasn’t enough to fully replenish his iPhone 7’s battery twice), Peter Bonahoom filed a nationwide class action against Staples that contends four models of its “power bank chargers” — advertised as …