test.py
print(__name__)
output
__main__
test2.py
import test
output
test
When test.py is executed directly, str type main is assigned to name. Also, when test.py is imported from the outside, the str type file name test is assigned. In other words
if __name__ == '__main__':
main()
Main () is not executed when it is imported from the outside, it is executed only when it is executed directly.