code: func (o *OAuthSession) Vote(v Voter, dir Vote) error {
  	// Build form for POST request.
  	form := url.Values{
  		"id":  {v.voteID()},
  		"dir": {string(dir)},
  	}
  	var vo interface{}
  
  	err := o.postBody("https://oauth.reddit.com/api/vote", form, vo)
  	if err != nil {
  		return err
  	}
  	return nil
  }
docs: // Vote either votes or rescinds a vote for a Submission or Comment using OAuth.