@classmethod
    @gen.engine
    def delete_bulk_async(klass, to_delete, callback):
        from Mojo.ServerHelpers.RunServer import BACKEND_COLLECTION, DATABASE


        if DATABASE:
            if BACKEND_COLLECTION:
                this_collection = BACKEND_COLLECTION(DATABASE, klass)
                ret_obj = yield gen.Task(this_collection.delete, to_delete)

                callback(ret_obj)
A recursive transformation pipeline
dataset/ETHPy150Open lonelycode/Mojo/Mojo/ObjectMapper/ModelPrototype.py/Model.delete_bulk_async--crossover with--dataset/ETHPy150Open bmcfee/muda/muda/base.py/Pipeline.__recursive_transform