Function has_finalizer

Return true if object has a finalization method. * CAUTION: An instance of an old-style class has to be checked for a *__del__ method, and earlier versions of this used to call PyObject_HasAttr, * which in turn could call the class's __getattr__ hook (if any). That * could invoke arbitrary Python code, mutating the object graph in arbitrary * ways, and that was the source of some excruciati