the python idiom if __name__ == '__main__' allows the creation of modules that code example

Example 1: python if __main__

#Add this code to run a support module on its own.
#Great for running quick tests.

if __name__ == "__main__":
	function_that_starts_the_module_to_run_on_its_own() 
    #or
    test_function_included_in_module()

Example 2: explained if name main python

python foo.py