'MultiPartParser.parse() leaves request.POST immutable.'

def test_POST_immutable_for_mutipart(self):

    payload = FakePayload('\r\n'.join(['--boundary', 'Content-Disposition:    form-data;    name="name"', '', 'value', '--boundary--']))
    request = WSGIRequest({'REQUEST_METHOD': 'POST', 'CONTENT_TYPE': 'multipart/form-data;    boundary=boundary', 'CONTENT_LENGTH': len(payload), 'wsgi.input': payload})
    self.assertFalse(request.POST._mutable)
