def get_docs_to_commit(self):
        try:
            spec = {'synced': False}
            fields = {'_id': 0}
            cur = self.db.docs.find(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        return list(cur)
def block_size_filter(entity):
        return (
            entity.size[0] * 2 >= entity.size[1] * 2
            and entity.size[1] <= 16
            and entity.size[3] <= 4
        )