multiporcessing in task throwd daemonic processes are not allowed to have children

[mtaohuang]

Apache Airflow version:
2.0

Environment:
Python3.6

What happened:
I used mutiprocessing Process in PythonOperator callable function, but it reports an error.

File "/home/xxx/airflow/dags/Gen/SecData.py", line 88, in gen
w.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

What you expected to happen:
In airflow1.10, I could use multiprocessing in task function, it works well,
I'm not sure if is't a bug or there are other ways to use multiporcessing in PythonOperator task function.

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template!

[mtaohuang]

export PYTHONOPTIMIZE=1
solved the problem

[raphaelauv]

explanation there -> https://stackoverflow.com/a/57493983