def METHOD_NAME(self):
    config = AttributeGetter({
            "base_url": (lambda: ""),
            "has_access_token": (lambda: False),
            "has_client_credentials": (lambda: False),
            "public_key": "",
            "private_key": ""})
    headers = Http(config, "fake_environment")._Http__headers(Http.ContentType.Xml)
    self.assertTrue('Accept-Encoding' in headers)
    self.assertEqual('gzip', headers["Accept-Encoding"])