def METHOD_NAME(fresh_database):
   assert 'dummy_property' in db.get_halo("dummy_sim_1/step.1/halo_1")
   tool = property_deleter.PropertyDeleter()
   tool.parse_command_line("dummy_property --for dummy_sim_1/step.1 -f".split())
   tool.run_calculation_loop()
   # check deleted:
   assert 'dummy_property' not in db.get_halo("dummy_sim_1/step.1/halo_1")
   assert 'dummy_property' not in db.get_halo("dummy_sim_1/step.1/halo_2")
   # hasn't affected other steps or simulations:
   assert 'dummy_property' in db.get_halo("dummy_sim_1/step.2/halo_1")
   assert 'dummy_property'  in db.get_halo("dummy_sim_2/step.1/halo_1")