python multiprocessing pool：pool objects cannot be passed between processes or pickled

在类中把进程池设为成员变量，同时把self作为参数传给线程池中的函数的时候会报错：

pool objects cannot be passed between processes or pickled

两种方法解决:
第一种

class Test(object):
    def run(self):  
        self.pool=Pool(2)
        self.pool.starmap(func, [(xx,yy), (xx, yy)])

    def __getstate__(self):
        self_dict = self.__dict__.copy()
        del self_dict['pool']

        return self_dict

    def __setstate__(self, state):
        self.__dict__.update(state)

第二种:

class Test(object):
    def run(self):  
        with Pool(2) as pool:
        	pool.starmap(func, [(xx,yy), (xx, yy)])

参考: https://www.ikaze.cn/article/27