code: func (c *Client) APIReq(v interface{}, meth, path string, body interface{}, headers http.Header) error {
  	req, err := c.NewRequest(meth, path, body, headers)
  	if err != nil {
  		return err
  	}
  	return c.DoReq(req, v)
  }
docs: // Sends a Heroku API request and decodes the response into v. As
  // described in NewRequest(), the type of body determines how to
  // encode the request body. As described in DoReq(), the type of
  // v determines how to handle the response body.