code: def get_task_signature(cls, instance, serialized_instance, **kwargs):
          
          cleanup_tasks = [
              ProjectResourceCleanupTask().si(
                  core_utils.serialize_class(executor_cls),
                  core_utils.serialize_class(model_cls),
                  serialized_instance,
              )
              for (model_cls, executor_cls) in cls.executors
          ]
  
          if not cleanup_tasks:
              return core_tasks.EmptyTask()
  
          return chain(cleanup_tasks)
docs: Delete each resource using specific executor.
          Convert executors to task and combine all deletion task into single sequential task.