fix this breaking change

src/exit.rs

@@ -74,8 +74,8 @@ impl FromStr for Exit {
 
         let position = position.unwrap();
 
-        let effect = if let Some(transition_line) = parts.next() {
-            Transition::from(transition_line)
+        let effect = if parts.next().is_some() {
+            Transition::from(parts.next().unwrap())
         } else {
             Transition::None
         };