How to use the sqlitedict.SqliteDict.__nonzero__ function in sqlitedict

return

        logger.info("deleting %s" % self.filename)
        try:
            if os.path.isfile(self.filename):
                os.remove(self.filename)
        except (OSError, IOError):
            logger.exception("failed to delete %s" % (self.filename))

    def __del__(self):
        # like close(), but assume globals are gone by now (do not log!)
        self.close(do_log=False)

# Adding extra methods for python 2 compatibility (at import time)
if major_version == 2:
    SqliteDict.__nonzero__ = SqliteDict.__bool__
    del SqliteDict.__bool__  # not needed and confusing
#endclass SqliteDict


class SqliteMultithread(Thread):
    """
    Wrap sqlite connection in a way that allows concurrent requests from multiple threads.

    This is done by internally queueing the requests and processing them sequentially
    in a separate thread (in the same order they arrived).

    """
    def __init__(self, filename, autocommit, journal_mode):
        super(SqliteMultithread, self).__init__()
        self.filename = filename
        self.autocommit = autocommit

except (OSError, IOError):
            logger.exception("failed to delete %s" % (self.filename))

    def __del__(self):
        # like close(), but assume globals are gone by now (do not log!)
        try:
            self.close(do_log=False, force=True)
        except Exception:
            # prevent error log flood in case of multiple SqliteDicts
            # closed after connection lost (exceptions are always ignored
            # in __del__ method.
            pass

# Adding extra methods for python 2 compatibility (at import time)
if major_version == 2:
    SqliteDict.__nonzero__ = SqliteDict.__bool__
    del SqliteDict.__bool__  # not needed and confusing
#endclass SqliteDict


class SqliteMultithread(Thread):
    """
    Wrap sqlite connection in a way that allows concurrent requests from multiple threads.

    This is done by internally queueing the requests and processing them sequentially
    in a separate thread (in the same order they arrived).

    """
    def __init__(self, filename, autocommit, journal_mode):
        super(SqliteMultithread, self).__init__()
        self.filename = filename
        self.autocommit = autocommit