How to use the wpcom-xhr-request.put function in wpcom-xhr-request

Comment.prototype.update = function (query, body, fn) {
  if ('function' === typeof body) {
    fn = body;
    body = query;
    query = {};
  }

  body = 'string' === typeof body ? { content: body } : body;

  var path = '/sites/' + this._sid + '/comments/' + this._cid;
  return request.put(this.wpcom, null, path, query, body, fn);
};

Media.prototype.update = function (query, body, fn) {
  var path = '/sites/' + this._sid + '/media/' + this._id;
  return request.put(this.wpcom, def, path, query, body, fn);
};

Follow.prototype.add = function (query, fn) {
  var path = '/sites/' + this._sid + '/follows/new';
  return request.put(this.wpcom, null, path, query, null, fn);
};

Post.prototype.update = function (query, body, fn) {
  var path = '/sites/' + this._sid + '/posts/' + this._id;
  return request.put(this.wpcom, null, path, query, body, fn);
};