how to define main in python

1def main():
2    print("Hello World!")
3
4if __name__ == "__main__":
5    main()

1# Defining main function 
2def main(): 
3    print("hello World") 
4  
5  
6# Using the special variable  
7# __name__ 
8if __name__=="__main__": 
9    main() 

1
2print("Hello")
3
4print("__name__ value: ", __name__)
5
6
7def main():
8    print("python main function")
9
10
11if __name__ == '__main__':
12    main()
13