def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
def lazy_gettext(self, text: str, lang: str = None):
        if not babel_imported:
            raise RuntimeError('babel module is not imported. Check that you installed it.')
        return LazyProxy(self.gettext, text, lang, enable_cache=False)