code: def bulk_delete(self, container, object_names, async_=False):
          
          deleter = BulkDeleter(self, container, object_names)
          deleter.start()
          if async_:
              return deleter
          while not deleter.completed:
              time.sleep(self.bulk_delete_interval)
          return deleter.results
docs: Deletes multiple objects from a container in a single call.
  
          The bulk deletion call does not return until all of the specified
          objects have been processed. For large numbers of objects, this can
          take quite a while, so there is an 'async_' parameter to give you the
          option to have this call return immediately. If 'async_' is True, an
          object is returned with a 'completed' attribute that will be set to
          True as soon as the bulk deletion is complete, and a 'results'
          attribute that will contain a dictionary (described below) with the
          results of the bulk deletion.
  
          When deletion is complete the bulk deletion object's 'results'
          attribute will be populated with the information returned from the API
          call. In synchronous mode this is the value that is returned when the
          call completes. It is a dictionary with the following keys:
  
              deleted - the number of objects deleted
              not_found - the number of objects not found
              status - the HTTP return status code. '200 OK' indicates success
              errors - a list of any errors returned by the bulk delete call
  
          This isn't available in swiftclient yet, so it's using code patterned
          after the client code in that library.