Fixed #23623 -- Reduced memory consumption when generating ModelChoiceField choices

        if self.field.cache_choices:

            if self.field.choice_cache is None:

                self.field.choice_cache = [

                    self.choice(obj) for obj in self.queryset.all()

                    self.choice(obj) for obj in self.queryset.iterator()

                ]

            for choice in self.field.choice_cache:

                yield choice

        else:

            for obj in self.queryset.all():

            for obj in self.queryset.iterator():

                yield self.choice(obj)

    def __len__(self):