title: How do I remove all stale branches from Github?
body: <p>We have a lot of branches that are inactive (the newest is 7 months old, the oldest is two years ago).<br>
  I'd like to remove all of those branches in bulk from the remote if no PR is still open for them.</p>
  
  <p>Should I be using Github's API? Should I be using git using snippets like those provided in <a href="https://stackoverflow.com/questions/10325599/delete-all-branches-that-are-more-than-x-days-weeks-old">this StackOverflow question</a>?<br>
  Is there some Github functionality I'm not familiar with that can help organize our repository?</p>