can we embed adobe sign document into web application using rest api?

I am using /widget rest api to get the embed code that I want to use in my web application. As per the doc guide this api shoudl return embed code as well, but it's only returning key never the embed code that I can include in javascript. https://opensource.adobe.com/acrobat-sign/developer_guide/apiusage.html#widget 

Does anyone have idea how to get this code using rest api?