def get_file(self, key):
        f = open(os.path.join(self._path, self._lookup(key)), 'rb')
        return _ProxyFile(f)
Returns a channel with credentials callback.
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/Maildir.get_file--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/cloud-pubsub-samples-python/grpc/pubsub_sample.py/make_channel_creds