Multiprocessing in bludit-3.9.2-bruteforce does not exit gracefully

[zweilosec]

In bludit-3.9.2_pwd-bruteforce_multi.py
The following error message occurs after finding a password for successful login.

    Process Process-7:
    Traceback (most recent call last):
      File "/usr/lib/python3.8/multiprocessing/process.py", line 315, in _bootstrap
        self.run()
      File "/usr/lib/python3.8/multiprocessing/process.py", line 108, in run
        self._target(*self._args, **self._kwargs)
      File "bludit-3.9.2-bruteForce-multi.py", line 59, in worker
        cleanup(procs)
      File "bludit-3.9.2-bruteForce-multi.py", line 99, in cleanup
        p.join()
      File "/usr/lib/python3.8/multiprocessing/process.py", line 147, in join
        assert self._parent_pid == os.getpid(), 'can only join a child process'
    AssertionError: can only join a child process

Expected behavior is to clean up all running threads and exit the program gracefully.