Question: What subject of Andy Warhol's film "Sleep" has sat in on  Bernadette Mayer's workshopts?
Sentence (from "Bernadette Mayer"): From 1980 to 1984, Mayer served as director of the Poetry Project, and her influence in the contemporary avant-garde is felt widely, with writers like Kathy Acker, Charles Bernstein, John Giorno, and Anne Waldman having sat in on her workshops.
Relevant evidence: Yes