anchor.diff:  
       let EmitAddedInterface (ai: InputJsonType.Root) =
           match ai.Extends with
  -        | Some e -> Pt.Printl "interface %s extends %s {" ai.Name.Value ai.Extends.Value
  +        | Some e -> Pt.Printl "interface %s extends %s {" ai.Name.Value e
           | None -> Pt.Printl "interface %s {" ai.Name.Value
   
           let emitProperty (p: InputJsonType.Property) =
  
positive.code:             | Some i' -> EmitAllMembers flavor i'
              | _ -> ()
  
      let EmitEventHandlers (flavor: Flavor) (prefix: string) (i:Browser.Interface) =
          let getOptionsType (addOrRemove: string) =
              if addOrRemove = "add" then "AddEventListenerOptions" else "EventListenerOptions"
  
  
negative.code: 
              let prefix = ""
              EmitMembers flavor prefix EmitScope.InstanceOnly i
              EmitEventHandlers prefix i
              EmitIndexers EmitScope.InstanceOnly i
  
              Pt.DecreaseIndent()
  