def __call__(self, request, *args, **kwargs):
        stage = {
            '1': 'preview',
            '2': 'post',
        }.get(request.POST.get(self.unused_name('stage')), 'preview')
        self.parse_params(request, *args, **kwargs)
        try:
            method = getattr(self, stage + '_' + request.method.lower())
        except __HOLE__:
            raise Http404
        return method(request)
dataset/ETHPy150Open django/django-formtools/formtools/preview.py/FormPreview.__call__