code: def _init_proc(self):
          
          if not self.proc:
              self.proc = [
                  mp.Process(target=self._proc_loop, args=(i, self.alive, self.queue, self.fn))
                  for i in range(self.num_proc)
              ]
              self.alive.value = True
              for p in self.proc:
                  p.start()
docs: Start processes if not already started