Python - google lesson - function call template

I watched several videos on YouTube from Google and in the main lessons showed how to create and call a function:

def main():
    print 'Hello'

if __name__ == '__main__':   # this is the boilerplate portion
    main()

Why do we need to take an additional step to create this template, if we can just look like this code:

def main():
    print 'Hello'

main()

The result will be the same without additional code.

-BK