code: def clean(self, exclude, max_count=None):
          
          return self.client.remove_objects(self.bucket, itertools.islice(
              (x.object_name for x in self.client.list_objects(self.bucket, self.remote_path + '/')
               if x not in exclude), max_count))
docs: Delete all objects except for those in the exclude
          :param exclude: a list of blob_hashes to skip.
          :param max_count: maximum number of object to delete
          :return: generator of objects that failed to delete