How to use the vega-scenegraph.render function in vega-scenegraph

var d3 = require('d3'),
    dl = require('datalib'),
    df = require('vega-dataflow'),
    sg = require('vega-scenegraph').render,
    log = require('vega-logging'),
    Deps = df.Dependencies,
    parseStreams = require('../parse/streams'),
    Encoder = require('../scene/Encoder'),
    Transition = require('../scene/Transition');

function View(el, width, height) {
  this._el    = null;
  this._model = null;
  this._width   = this.__width = width || 500;
  this._height  = this.__height = height || 300;
  this._bgcolor = null;
  this._cursor  = true; // Set cursor based on hover propset?
  this._autopad = 1;
  this._padding = {top:0, left:0, bottom:0, right:0};
  this._viewport = null;

var sg = require('vega-scenegraph').render,
    canvas = sg.canvas,
    svg = sg.svg.string,
    View = require('./View');

function HeadlessView(width, height, model) {
  View.call(this, width, height, model);
  this._type = 'canvas';
  this._renderers = {canvas: canvas, svg: svg};
}

var prototype = (HeadlessView.prototype = new View());

prototype.renderer = function(type) {
  if(type) this._type = type;
  return View.prototype.renderer.apply(this, arguments);
};