用PyV8来将js转python时，如何提取js中的json数据

当拿取jsObject中的json数据时（var_scene1.bgAudio），拿到的信息为空（希望拿到{"url":"a/b/c/d/e.mp3","name":"aaa.mp3"}）。
应该用什么办法获取？
谢谢

import PyV8

str_scene2 = """
var scene = {id:123321,bgAudio:{"url":"a/b/c/d/e.mp3","name":"aaa.mp3"}};
"""

s1 = str_scene2.decode('utf-8')
with PyV8.JSContext() as env1:
    env1.eval(s1)
    vars = env1.locals
    var_scene1 = vars.scene
    print var_scene1.id

    print var_scene1.bgAudio  # it shows [object Object]
    print type(var_scene1.bgAudio)  # it shows <class '_PyV8.JSObject'>