{"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"Some(Mutability::Mut)"}]}
                        Some(Mutability::Mut) => {
                        Some(Mutability::Not) => (".borrow()", "borrow", "a mutable borrow exists"),
                            (".borrow_mut()", "mutably borrow", "any borrows exist")