title: how to rollback a branch merge in mercurial
body: <p><a href="https://i.stack.imgur.com/3SEd3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3SEd3.png" alt="enter image description here"></a>I have merged my development branch with production by mistake. I haven't made it public, please let me know how can I revert back this merge ? 
  I am using TortoiseHG workbench. </p>