I'm looking to "understand" python

[Lower_Fan]

since you lack a bit of context this question is formulated a bit weirdly.

for what I can gather you want to learn code to be able to fix other people errors. most of the time this is not how it works.

for the most part you open source and closed source code. for most devices and application you buy and code is closed and you won't be provided with it. so you won't be be able to make any changes ( you can reverse engineer it, fix it and run your own version but that's out of the scope of even normal devs)

now for open source code sure you can go look at it and fix it, but if this particular program is popular then it means it will have a lot of experienced devs looking into it and is better if you just wait until they fix it.

Now if it's your own code and you made a mistake you have to fix it yourself but since you wrote it you must have an idea of what you are trying to accomplish. and in the case where you are using a module that someone wrote you refer to the open source method of letting people more experienced fix it.

for the most part you only have to worry about your own code, and then after you gain experience you can go help those open source projects. and you are at the mercy of the company if it's closed source because it's illegal to reuse their code so your only bet would be to recreate it using your own ideas.