code: def _repopulate_pool(self):
          
          for i in range(self._processes - len(self._pool)):
              w = self.Process(target=worker,
                               args=(self._inqueue, self._outqueue,
                                     self._initializer,
                                     self._initargs, self._maxtasksperchild,
                                     self._wrap_exception,
                                     self._finalizer,
                                     self._finalargs)
                               )
              self._pool.append(w)
              w.name = w.name.replace('Process', 'PoolWorker')
              w.daemon = True
              w.start()
              util.debug('added worker')
docs: Bring the number of pool processes up to the specified number, for use
          after reaping workers which have exited.