code: func (r *Resource) Put(options ...interface{}) (*Resource, error) {
  	if len(options) > 0 {
  		r.Payload = r.SetPayload(options[0])
  	}
  	return r.do("PUT")
  }
docs: // Performs a PUT request on given Resource.
  // Accepts interface{} as parameter, will be used as payload.