code: func (r *Result) Vector() (Vector, error) {
  	if r.Err != nil {
  		return nil, r.Err
  	}
  	v, ok := r.Value.(Vector)
  	if !ok {
  		return nil, errors.New("query result is not a Vector")
  	}
  	return v, nil
  }
docs: // Vector returns a Vector if the result value is one. An error is returned if
  // the result was an error or the result value is not a Vector.