At a time when the coronavirus is wreaking havoc on businesses around the world, the film industry in Nigeria's mainly Muslim north is going from strength to strength. The region's movie machine -- dubbed Kannywood after its largest city Kano -- has become the dominant source of entertainment for West Africa's 80 million Hausa speakers. And Northflix, Kannywood's fledgling online streaming platform, has seen its client base soar since authorities imposed lockdowns to contain the coronavirus pandemic in March.