Pycharm exit code 0

You realize it is not part of the output right? It's just additional information provided by the IDE's console. The real program is just outputting hellow as expected.

Saying that the Process finished with exit code 0 means that everything worked ok. If an exception occurs in your program or otherwise an exit is generated with non-zero argument, the IDE is gonna inform you about this, which is useful debug information.

You're not supposed to run your Python programs from the IDE when in production so I think trying to remove that is irrelevant.