title: How does git --no-merged option work
body: <p>How does the <code>git branch -r --no-merged</code> work?</p>
  
  <p>Does it check to see if all commits in one branch already exist in the original parent branch?</p>
  
  <p>And what about cherry picks? Is it smart enough to say that a commit from 1 branch has already been cherry picked back into the original parent branch?</p>
  
  <p>And if a branch has already been merged and new commits have been added will it pick that branch up as not being merged?</p>