code: def check_config_integrity(self):
          
          tasks_by_hash = {_hash_task(t): t for t in self.config_tasks}
  
          if len(tasks_by_hash) != len(self.config_tasks):
              raise Exception("Fatal error: there was a hash duplicate in the scheduled tasks config.")
  
          for h, task in tasks_by_hash.items():
              if task.get("monthday") and not task.get("dailytime"):
                  raise Exception("Fatal error: you can't schedule a task with 'monthday' and without 'dailytime' (%s)" % h)
              if task.get("weekday") and not task.get("dailytime"):
                  raise Exception("Fatal error: you can't schedule a task with 'weekday' and without 'dailytime' (%s)" % h)
  
              if not task.get("monthday") and not task.get("weekday") and not task.get("dailytime") and not task.get("interval"):
                  raise Exception("Fatal error: scheduler must be specified one of monthday,weekday,dailytime,interval. (%s)" % h)
docs: Make sure the scheduler config is valid