[Python] Why the print line will exec twice in a py file? [duplicate]

When learning python threading and process some wired code i do not understand

The question is

1. why the print line exec twice?
2. why gvar is 20 in proc1 init but gvar is 10 in proc1 run?

can anyone explain the principle why is it

The sample code and output follows

import multiprocessing
import os
import threading
from multiprocessing import freeze_support

print('why this will print twice? pid {} tid {}'.format(os.getpid(), threading.get_ident()))
gvar = 10


class Proc1(multiprocessing.Process):
def __init__(self):
super().__init__()
print('proc1 init pid {} tid {} gvar {}'.format(os.getpid(), threading.get_ident(), gvar))

def run(self) -> None:
print('proc1 run pid {} tid {} gvar {}'.format(os.getpid(), threading.get_ident(), gvar))


class Thread1(threading.Thread):
def __init__(self):
super().__init__()
print('thread1 init pid {} tid {} gvar {}'.format(os.getpid(), threading.get_ident(), gvar))

def run(self) -> None:
print('thread1 run pid {} tid {} gvar {}'.format(os.getpid(), threading.get_ident(), gvar))


if __name__ == '__main__':
freeze_support()
print('pid {} tid {} gvar {}'.format(os.getpid(), threading.get_ident(), gvar))

s = Thread1()
s.start()

gvar = 20

p = Proc1()
p.start()



and the out put is

why this will print twice? pid 38648 tid 31428
pid 38648 tid 31428 gvar 10
thread1 init pid 38648 tid 31428 gvar 10
thread1 run pid 38648 tid 26968 gvar 10
proc1 init pid 38648 tid 31428 gvar 20
why this will print twice? pid 27380 tid 19716
proc1 run pid 27380 tid 19716 gvar 10

Continue reading...