Chicago has turned into Gotham City, and there’s no superhero watching for the Bat Signal. But instead of just giving in, one Chicago woman defended herself when a punk pulled a gun on her. On Wednesday afternoon, a student identified only as Maddi was walking home from class around 3 p.m. in the 5600 block of South University Avenue when a masked man approached and attempted to rob her at gunpoint. “I was just walking home from class and I see a man in a mask approach me,” Maddi told WLS-TV. “And he kind of comes towards me, and I think to myself, ‘just keep walking,’ but then we have an alte…