if len(owes_list) > 0:
raise DirtyBooks, ("People still owe money", owes_list)
if len(owed_list) > 0:
raise DirtyBooks, ("People are still owed money", owed_list)
if len(owes_list) > 0:
raise DirtyBooks, ("People still owe money", owes_list)
if len(owed_list) > 0:
raise DirtyBooks, ("People are still owed money", owed_list)