code: def output(self):
          
          if self.task.target_collection_cls is not None:
              cls = self.task.target_collection_cls
          elif self.task.outputs_siblings:
              cls = SiblingFileCollection
          else:
              cls = TargetCollection
  
          targets = luigi.task.getpaths(self.task.get_branch_tasks())
          collection = cls(targets, threshold=self.threshold(len(targets)))
  
          return OrderedDict([("collection", collection)])
docs: Returns the default workflow outputs in an ordered dictionary. At the moment this is just
          the collection of outputs of the branch tasks, stored with the key ``"collection"``.