title: How to find out promoted tweets from twitter?
body: <p>I'm currently doing a project on Twitter data, and I'd like to identify whether the tweets are promoted or not.
  I mean, you guys can see promoted tweets from your homepage all the time, but I collect some of them and couldn't find any clear label called promoted from the source field.
  Does anyone have any idea how to identify these?</p>
  
  <p>Thank you!</p>