def handle_407(self, r, **kwargs):
        proxy_authenticate = r.headers.get('Proxy-Authenticate', '').lower()

        if 'basic' not in proxy_authenticate:
            return self._handle_basic_auth_407(r, kwargs)

        if 'digest' in proxy_authenticate:
            return self._handle_digest_auth_407(r, kwargs)
dataset/ETHPy150Open sigmavirus24/requests-toolbelt/requests_toolbelt/auth/guess.py/GuessProxyAuth.handle_407/operator `in` -> `not in`