title: Google Youtube Data API: Private videos with API key
body: <p>So we have some training videos on youtube that are private. We want people that log into our system to be able to access those videos, but I don't want them to have to login with oauth.</p>
  
  <p>I want our app to do the authentication to OUR account and when our app uses the api, I want it to return private videos. (I'm fine with using the API key and limiting the referral)</p>
  
  <p>I've played around with the api, but the api key does not return private videos.</p>
  
  <p>It always return an empty array of items.</p>
  
  <p>How can I do this?</p>