diff --git a/observation_sim/sim_steps/add_objects.py b/observation_sim/sim_steps/add_objects.py
index 49707d44ffc2faf87712da0428fb5bea9b6c6f39..0d89b938b181f3693a77d2829985af1dd12958d5 100644
--- a/observation_sim/sim_steps/add_objects.py
+++ b/observation_sim/sim_steps/add_objects.py
@@ -10,6 +10,7 @@ from observation_sim.psf import PSFGauss, FieldDistortion, PSFInterp, PSFInterpS
 from astropy.time import Time
 from datetime import datetime, timezone
 
+
 def _is_obj_valid(self, obj):
     if obj.param['star'] == 4:
         # Currently there's no parameter checks for 'calib' type