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 signal_handler_mapping(self):
        """A dict mapping (signal number) -> (a method handling the signal)."""
        # Could use an enum here, but we never end up doing any matching on the specific signal value,
        # instead just iterating over the registered signals to set handlers, so a dict is probably
        # better.
        return {
            signal.SIGINT: self._handle_sigint_if_enabled,
            signal.SIGQUIT: self.handle_sigquit,
            signal.SIGTERM: self.handle_sigterm,
        }