diff --git a/arc/scheduler.py b/arc/scheduler.py
index d8317d748b..2f85ea0a81 100644
--- a/arc/scheduler.py
+++ b/arc/scheduler.py
@@ -767,7 +767,7 @@ def run_job(self,
             args['shift'] = shift
         if scan_trsh:
             args['keyword']['scan_trsh'] = scan_trsh
-        if level_of_theory is not None and level_of_theory.args is not None:
+        if isinstance(level_of_theory, Level) and level_of_theory.args is not None:
             args.update(level_of_theory.args)
 
         job = job_factory(job_adapter=job_adapter,