async def METHOD_NAME(self, size=None) -> StorageFileObject:
    if size is None:  # pragma: no cover
        raise ValueError("size must be provided for shared memory backend")
    new_id = self._generate_object_id()
    shm_file = SharedMemoryFileObject(new_id, size=size, mode="w")
    return ShmStorageFileObject(shm_file, object_id=new_id)