In perl debugger I can use DB::get_fork_TTY() to debug both parent and child process in different terminals.  Is there anything similar in python debugger?
Or, is there any good way to debug fork in python?
But I'm still curious if there's any similar feature in python debugger. I happen to find this feature in perldb and I find it's very handy

No.
You don't need it.
No matter how handy it may appear in other environments, you just don't need it.
You don't need fork() in Python; therefore you don't need fancy debugging to work with fork().
If you think you need fork() you should either use subprocess, multiprocessing or C.
How to debug python scripts that fork