Hi, @codingeinstiensface ,
See @bandit's reply regarding the indentation. When you post code, be sure to format it, so that we can see how it is indented. For instructions on how to format posted code, consult How do I format code in my posts?.
After you have defined your function, you must call it, if you would like to it execute. Since you did not call your function, nothing got printed. In order to call your
hello_world function, add the following line to your code ...
Be sure not to indent that line, otherwise it will become part of the function definition.