code: def pause_process(self, key):
          
          if key in self.processes and key not in self.paused:
              os.killpg(os.getpgid(self.processes[key].pid), signal.SIGSTOP)
              self.queue[key]['status'] = 'paused'
              self.paused.append(key)
              return True
          return False
docs: Pause a specific processes.