This is less for the person that asked the question but more for people like myself that come here from Python Crash Course with the same question and don't get the answer they were looking for:
If, like me, you were running the code from your text editor (in my case VS Code), it's possible that the terminal window within the editor wasn't in the proper directory. I didn't realize myself, because I was thinking that because I opened the .py file from the correct working directory in the terminal that everything should work as planned. It wasn't until I realized that the terminal in the editor is a separate instance (thus making the present working directory home instead of my folder for PCC work) that I was able to get the program to run as intended.
In short, navigate to the proper directory in your editor's terminal instance and the program should run as intended.
Hope this helps!
image with terminal open on desktop and in text editor to show working directory difference