A Python File Should Contain "main()" Function

I think I found a recipe for a new Python file:

def ...(): ...
def ...(): ...

def main():
    ...
    ...

if __name__ == '__main__':
    main()

Instead of putting everything in main() plainly under the if statement.

Why ? I have a list:

1. You should not be able to create and mutate global vars at will and during runtime! Under the if statement, any var declared will be global.

2. It just harder for IDE to help us auto-suggesting the code. The IDE will not know whether a var or a function declared under the if statement will be available at the runtime or not. This is a bad thing because the auto-suggestion list will contain a bunch of choices that doesn’t work.

3. And, it’s also easier for unit-testing. Instead of indirectly running a .py file, we can direct this into just using a function call.