def async_exists(self, callback, key):
        self._schedule(self.store_exists_async,
                       key=key, callback=callback)
Returns the authentication URL for this service.
dataset/ETHPy150Open kivy/kivy/kivy/storage/__init__.py/AbstractStore.async_exists--crossover with--dataset/ETHPy150Open IanLewis/kay/kay/ext/gaema/auth.py/OpenIdMixin.authenticate_redirect