code: func NewScanFloat64Handler(f *float64) ReplyHandler {
  	return func(reply interface{}) error {
  		var err error
  		(*f), err = redis.Float64(reply, nil)
  		if err != nil {
  			return err
  		}
  		return nil
  	}
  }
docs: // NewScanFloat64Handler returns a ReplyHandler which will convert the reply to a
  // float64 and set the value of f to the converted value. The ReplyHandler
  // will return an error if there was a problem converting the reply.