You've probably already got it, I'm surveying several sites to improve programming skills. This episode is about Codecademy.
You'll be required to actually write code and run it! yes, the code you write is then executed in a web "interpreter" (modified for educational purposes) and the output displayed on screen. In a section is also possible to write to files and have their contents shown on another tab.
I'd encourage you to start from it if you never saw Python and you're willing to learn if from the ground up.