def get_callback(self, request_token):
        raise NotImplementedError("Must be implemented by inheriting classes")
Fetch a URL, optionally caching for a specified time.
dataset/ETHPy150Open ib-lundgren/flask-oauthprovider/flask_oauthprovider.py/OAuthProvider.get_callback--crossover with--dataset/ETHPy150Open livid/v2ex/twitter/twitter.py/Api._FetchUrl