I have my string foo here, and I need to convert it to upper case letters. I know that's possible, but instead of going to Stack Overflow or Google, I can use the dir method in Python and provide the object in question. Whenever I run that, it gives me a list of everything that's possible with that object. It knows that this is a string, so it only gives me string-based operations.
In the output here, the first thing you see are these double under methods. They're called double unders because they start with a double underscore. These methods aren't intended for you to call them directly, but they do show you the possible operations. For example, if I wanted to add foo plus bar, that actually uses the __add method, but I used the plus symbol instead of calling it directly.
Back to my current problem though, of how to convert it to upper case, I look at the rest of the methods here and there's one called upper. Sounds like what I need.
To see how to use it, I can call Python's built-in help system and provide my string plus the method that I'm trying to figure out how to use. That opens up the built-in help menu, it shows me that if I call the string with the .upper method, it'll return a copy of the string converted to upper case. Let's try that out. I'll say foo.upper, and there it is, all upper case letters.