An attempt has been made to start a new process before the current process has finished its bootstrapping phase. This probably means that you are not using fork to start your child processes and you have forgotten to use the proper idiom in the main module: if __name__ == '__main__': freeze_support() ... The "freeze_support()" line can be omitted if the program is not going to be frozen to produce an executable.

运行时错误:在当前进程完成引导阶段之前已经尝试启动新进程。这可能意味着您没有使用 fork 来启动子进程，并且忘记在主模块中使用适当的习语:
if __name__ == __main__:
freeze_support()
...
如果程序不会被冻结以生成可执行文件，则可以省略 "freeze_support()" 行。