No way to merge sketch files
This might not be clear enough, or maybe I am doing something wrong. 

Situation:
- I make changes to my `ui.sketch` file. My co-worker makes changes to his `ui.sketch` file.
- I stash my changes into a new branch, no biggie.
- My co-worker commits, I pull in his changes.
- I want to put merge my branch with my previous `ui.sketch` changes into the now updated master with his changes.

`ui.sketch` is now a conflict with no way to resolve. I understand merging these files probably isn't possible.

Am I correct?