code: func NewScanBoolHandler(b *bool) ReplyHandler {
  	return func(reply interface{}) error {
  		var err error
  		(*b), err = redis.Bool(reply, nil)
  		if err != nil {
  			return err
  		}
  		return nil
  	}
  }
docs: // NewScanBoolHandler returns a ReplyHandler which will convert the reply to a
  // bool and set the value of i to the converted bool. The ReplyHandler
  // will return an error if there was a problem converting the reply.