Add djcelery.schedulers.DatabaseScheduler judgment custom class

In my project, because of many reasons to use one django orm storage all djcelery_periodictask. But there are several beat distributed on different servers, Cause the business needs, I inherited djcelery.schedulers.DatabaseScheduler class customized some implementations, but djcelery template I have not prompted to use the correct DatabaseScheduler module,

I looked under the code because it simply verifies whether settings.py set CELERYBEAT_SCHEDULER is 'djcelery.schedulers.DatabaseScheduler', rather than to verify whether the specified configuration inherited from djcelery.schedulers.DatabaseScheduler