message: Implement PropertyList::short_repr()
diff: @@ -24,7 +24,9 @@ impl ObjectClass for PropertyList {
  &self.0
  }
  - // TODO: short_repr()
  + fn short_repr(&self) -> Option<String> {
  + Some(self.class().map(|c| c.to_string()).unwrap_or_else(|_| "unknown class".to_owned()))
  + }
  }
  impl Debug for PropertyList {
  