import gc
classold_style_class():passclassnew_style_class(object):pass
a =old_style_class()del a
gc.collect()
b =new_style_class()del b
gc.collect()
a =old_style_class()del old_style_class
gc.collect()
b =new_style_class()del new_style_class
gc.collect()del a
gc.collect()del b
gc.collect()