name 3d 3d main in python

1# If the python interpreter is running that module (the source file)
2# as the main program, it sets the special __name__ variable to have
3# a value “__main__”. If this file is being imported from another 
4# module, __name__ will be set to the module’s name.
5if __name__=='__main__':
6  # do something

1if __name__ == "__main__": main()