remove unused fn

src/game.rs

@@ -34,20 +34,6 @@ impl RoomFormat {
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 pub enum RoomType {Room, Set}
 
-#[derive(Debug)]
-pub struct InvalidRoomType;
-
-impl RoomType {
-    #[inline]
-    fn from(string: &str) -> Result<RoomType, InvalidRoomType> {
-        match string {
-            "ROOM" => Ok(RoomType::Room),
-            "SET"  => Ok(RoomType::Set),
-            _ => Err(InvalidRoomType),
-        }
-    }
-}
-
 impl ToString for RoomType {
     #[inline]
     fn to_string(&self) -> String {