code: public SmartBinder append(String name, Object value) {
          return new SmartBinder(this, signature().appendArg(name, value.getClass()), binder.append(value));
      }
docs: Append the given argument to the argument list, assigning it the
  given name.
  
  @param name  the name of the new argument
  @param value the value of the new argument
  @return a new SmartBinder with the append applied