“Young Adult” screenwriter Diablo Cody sees similarities between the movie’s hard-drinking main character Mavis, played by Charlize Theron, and Chelsea Handler. “I just taped a segment at ‘Chelsea Lately,’ where we joked about how Mavis is like Chelsea,” Cody tells The Post’s Mandy Stadtmiller. “Chelsea is actually, like, the warmest, most generous, selfless person. But the persona she’s built up has those elements of, you know: drunk, critical. But she’s not.” Cody’s husband, Dan Maurio, is a producer on “Chelsea Lately.” Theron’s character in the film is trying to break up a marriage, but Cody says that’s not drawn from her own experience. “I would be way smarter about it if I wanted to steal someone’s man,” she cracked. But there are some details that seem to mirror real life: Theron’s character is the ghostwriter of a young-adult book series, and Cody says she’s moving ahead on a script based on the “Sweet Valley High” ’80s teen tomes.