python报错记录 AssertionError: daemonic processes are not allowed to have children

Process Process-2:
Traceback (most recent call last):
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "main.py", line 75, in mf_insp
    with Manager() as manager:
  File "/usr/lib64/python3.6/multiprocessing/context.py", line 56, in Manager
    m.start()
  File "/usr/lib64/python3.6/multiprocessing/managers.py", line 513, in start
    self._process.start()
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 103, in start
    'daemonic processes are not allowed to have children'
AssertionError: daemonic processes are not allowed to have children

from multiprocessing import Process
import os

def f():
        print("F: {pid}".format(pid=os.getpid()))
        p = Process(target=c,)
        p.start()
        p.join()

def c():
        print("C: {pid}".format(pid=os.getpid()))

if __name__ == '__main__':
        thread_list={}
        for i in range(4):
                thread_list[i] = Process(target=f, daemon=True)
        for i in range(4):
                thread_list[i].start()
        for i in range(4):
                thread_list[i].join()