def has_upload(self, filename):
    return filename in self.uploads
HMAC a value with a key, hex output
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/files/file_service_stub.py/GoogleStorage.has_upload--crossover with--dataset/ETHPy150Open benadida/helios-server/helios/utils.py/do_hmac