Update python/grass/jupyter/test_region.py

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: AkshadSonawane

python/grass/jupyter/test_region.py

@@ -15,9 +15,8 @@ def run_in_subprocess(file):
         [sys.executable, os.fspath(file)], capture_output=True, text=True, env=env
     )
     if process.returncode != 0:
-        raise AssertionError(
-            f"Subprocess script failed.\nStderr: {process.stderr}\nStdout: {process.stdout}"
-        )
+        msg = f"Subprocess script failed.\nStderr: {process.stderr}\nStdout: {process.stdout}"
+        raise AssertionError(msg)
     return process.stdout