def configure_response(self, content=b'', proxy_manager=None, url=None,
                           reason=b''):
        self.adapter.proxy_manager = proxy_manager or {}
        self.response.content = content
        self.response.url = url
        self.response.reason = reason
A formset with instance=None can be created. Regression for #11872
dataset/ETHPy150Open sigmavirus24/requests-toolbelt/tests/test_dump.py/RequestResponseMixin.configure_response--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.3/tests/regressiontests/model_formsets_regress/tests.py/InlineFormsetTests.test_formset_with_none_instance