anchor.diff:          ]
   
       let Event =
  -        Interface "L.Event"
  -        |+> [
  +        Class "L.Event"
  +        |+> Protocol [
               "type" =? T<string>
               |> WithComment "The event type (e.g. 'click')."
               "target" =? T<obj>
  
positive.code:         ]
  
      let TileEvent =
          Interface "L.TileEvent"
          |=> Extends [Event]
          |+> [
              "tile" =? T<Element>
              |> WithComment "The tile element (image)."
              "url" =? T<string>
  
negative.code:         ]
          |+> Protocol [
              // Methods
              "setView" => LatLngOrCoords?center * !?T<int>?zoom * !?ZoomPanOptions?options ^-> T<unit>
              |> WithComment "Sets the view of the map (geographical center and zoom) with the given animation options."
              "setZoom" => T<int>?zoom * !?ZoomOptions?options ^-> T<unit>
              |> WithComment "Sets the zoom of the map."
  