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 applies(cls, obj):
        if not cls.loaded():
            return False
        import cudf
        return isinstance(obj, (cudf.DataFrame, cudf.Series))