def insert(self, doc, synced=False):
        doc.id = self.get_next_id()
        doc.synced = synced
        try:
            self.db.docs.insert(doc)
        except Exception as e:
            raise DatabaseException(e)
        return doc
def test_impl():
            A = np.array([1., 2., 3.])
            A[0] = np.nan
            df = pd.DataFrame({'A': A})
            df.A.fillna(5.0, inplace=True)
            return df.A.sum()