    def _log_format_default(self):
        """override default log format to include time"""
        return "%(color)s[%(levelname)1.1s %(asctime)s.%(msecs).03d %(name)s %(module)s:%(lineno)d]%(end_color)s %(message)s"
override default log format to include time
jupyterhub/singleuser/mixins.py