def find_extra(self, old_record):
        rv = vars(old_record).copy()
        for key in ('name', 'msg', 'args', 'levelname', 'levelno',
                    'pathname', 'filename', 'module', 'exc_info',
                    'exc_text', 'lineno', 'funcName', 'created',
                    'msecs', 'relativeCreated', 'thread', 'threadName',
                    'greenlet', 'processName', 'process'):
            rv.pop(key, None)
        return rv
Tries to find custom data from the old logging record.  The
dataset/ETHPy150Open getlogbook/logbook/logbook/compat.py/RedirectLoggingHandler.find_extra