Unable to a add job to schedule. Job is not associated with an scheduler

Raise code

""" am job_func: The function to be scheduled
        :return: The invoked job instance
        """
        self.job_func = functools.partial(job_func, *args, **kwargs)
        functools.update_wrapper(self.job_func, job_func)
        self._schedule_next_run()
        if self.scheduler is None:
            raise ScheduleError(
                "Unable to a add job to schedule. "
                "Job is not associated with an scheduler"
            )
        self.scheduler.jobs.append(self)
        return self

    @property
    def shou