Questions about attributes and self

In Python, pass means "Something will be here in the future, but not right now. Just leave this empty and continue". You'll generally never see this in shipping code, but it's nice when you're building something so that you can build out some parts of your app before others, but still be able to check syntax and such along the way

In Python, self represents a single instance of your class (specifically, the one you're working on), and not the class itself. In fact, calling it self is actually just a convention, and you can name it whatever you'd like. For example, this is totally fine:

class Printer:
    def __repr__(this):
        print(this.string)

    def __init__(this, string):
        this.string = string

    def dump(this):
        print(this.string)

Note how in the above example, I used the word this instead of self, but if you paste it into a file and run it, it still works just fine.

Now, let's say that I want to call the dump function. I can do this in either of 2 ways:

• Printer("Something").dump()
• Printer.dump(Printer("Something"))

Both of these examples will print the string "Something" to your console. In the first example, Python knows what to use for self because you called dump on a specific instance, so Python passes that instance to dump as the first parameter. In the second, you've called the dump function on the Printer class and not on a specific instance, so you have to provide the value for self yourself by manually passing the function an instance of the Printer class. Both of these lines are exactly equivalent, but the 2nd is generally considered bad style, so you should generally always use the 1st way of doing it

I know this is counterintuitive, but Python doesn't actually know/care what you name your variables. This is pretty low-level and isn't really something you ever need to think about in your day-to-day programming, but when you make a variable, what Python sees is "I can find a bit of data at this address in memory", and not actually the specific name of your variable

If you print out an instance of an object, Python needs to convert it to a string. By default, every object converts itself to a string in the format of <modulename.ClassName object at 0xfffff> where modulename is name of the file where the class is declared, ClassName is the name of the class, and 0xfffff is the memory address of that instance. If you'd like to change this behavior, you can provide a custom implementation of either the special __str__ or __repr__ functions for your class, like I did for Printer in the example above

The answer to your last question is basically the same as the answer to your second question. Those are 2 different ways of doing the exact same thing. Calling kenneth.pickpocket() is exactly the same as calling Thief.pickpocket(kenneth). In the first way, Python knows what instance to provide for self because you called the pickpocket method on that instance, and in the 2nd, you're manually providing the instance for self yourself