code: func (c *Client) Update(path string, value interface{}, params map[string]string) error {
  	body, err := json.Marshal(value)
  	if err != nil {
  		log.Printf("%v\n", err)
  		return err
  	}
  
  	_, err = c.api.Call("PATCH", c.Url+"/"+path, c.Auth, body, params)
  
  	// if we've just updated the root node, clear the value so it gets looked up
  	// again and populated correctly since we just applied a diffgram
  	if len(path) == 0 {
  		c.value = nil
  	}
  
  	return err
  }
docs: // Update performs a partial update with the given value at the specified path.