code: def __lazy_migration(self, master_id):
          
          collection_name = self.request.headers.get("collection")
  
          if collection_name:
              stack = AsyncSchedulableDocumentRevisionStack(collection_name,
                                                            self.settings,
                                                            master_id=master_id,
                                                            )
              objects = yield stack._lazy_migration(meta=self._get_meta_data())
              raise Return(objects)
  
          self.raise_error(500, "This object %s/%s didn't exist as a revision, "
                           "we tried to create it but we failed... Sorry. "
                           "Please check this object" % (collection_name,
                                                         master_id))
          raise Return(None)
docs: Creates a revision for a master id that didn't previously have a
          revision, this allows you to easily turn on revisioning for a
          collection that didn't previously allow for it.
  
          :param master_id:
          :returns: list of objects