Do not attempt to save patch with empty patch (#242)

* Fixed a potential error

I've ran into this error several times, where it says model_patch can't be None and ending the entire program.

* Do not attempt to save patch with empty patch

---------

Co-authored-by: Kilian Lieret <kilian.lieret@posteo.de>

run.py

@@ -274,7 +274,7 @@ def save_patch(traj_dir: Path, instance_id: str, info) -> Optional[Path]:
     patch_output_dir = traj_dir / "patches"
     patch_output_dir.mkdir(exist_ok=True, parents=True)
     patch_output_file = patch_output_dir / f"{instance_id}.patch"
-    if not "submission" in info:
+    if not info.get("submission"):
         logger.info("No patch to save.")
         return
     model_patch = info["submission"]