def add(self, key, value, timeout=DEFAULT_TIMEOUT, version=None,
            read=False, tag=None):
        # pylint: disable=arguments-differ
        if self.has_key(key, version):
            return False
        return self.set(
            key, value, timeout=timeout, version=version, read=read, tag=tag
        )
Set a value in the cache if the key does not already exist. If timeout is
dataset/ETHPy150Open grantjenks/python-diskcache/diskcache/djangocache.py/DjangoCache.add