把重要信息同时输出到日志和屏幕上

def print_log(file):
    def write_log(s):
        print(s)
        with open(file, 'a') as f:
            f.write(s+'\n')
    return write_log

print_log=utils.print_log('./train.log')
print_log("epoch:%d step:%d loss is:%s" % (epoch+1,i,train_loss))