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In addition to creating attributes, we know that we can also create methods.

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The attributes are the things that the object has and the methods

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are the things that the object does.

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Let's say that we were creating the car class and we've really created the seats

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attribute. Well, later on

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we might decide that we want to call a method to change that seats attribute's

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value. So for example, I've been watching a lot of truck racing recently.

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Yeah.

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[inaudible]

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And one of the things that people do when they mod their cars for racing is they

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take out some of the seats. This way it reduces the weight of the car,

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and it means that you can go a bit faster. So in our car class,

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we might, in fact,

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have a method where the car can enter race mode,

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where the seats are dropped from 5 to 2.

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This is what the method would look like. Inside the class declaration,

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we have a function, but remember when a function is attached to an object

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then it's called a method.

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This method looks exactly the same as how we've created other functions.

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We have the Def keyword, we have the name of the method,

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we have some parentheses which can take inputs, a colon,

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and then the body of the method. So in this case,

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all it does is it gets hold of the object and then the object seats attribute

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and then changes it to 2. So now when you call that method,

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all you need to do is get hold of the object and then you use the dot notation

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to call that method enter_race_mode, and of course,

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with the parentheses at the end.

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So let's say that while we're modeling our Instagram user,

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we want to have a way for the users to follow each other, right?

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And when they follow each other, their follower counts obviously go up.

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So let's define a new method. So we're going to use the def keyword

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and then we're going to name our method follow. Now a method,

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unlike a function, always needs to have a self parameter as the first parameter.

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This means that when this method is called,

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it knows the object that called it. Now,

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in addition to that self parameter,

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we're also going to pass in the user that we've decided to follow.

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So now let's say that we actually had two attributes,

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the followers and the following count, right?

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So they both start from zero, so two default attributes.

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But when a user decides to follow another user,

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well in this case,

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the user who we're following, their follower count goes up by one and our own,

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so the self.following count goes up by one as well.

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So the self keyword becomes quite important when we're working with classes and

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objects. It's a way for us to refer to the object 

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that's going to be created from this class inside the class blueprint.

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So you'll never see self when you're using objects

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but you see it a lot when you're writing your code inside your class.

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Now let's go ahead and call this.

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And let's say that user_1 decided to follow

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user_2. This is the user_1 object,

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and this is the follow method from the user_1 object.

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And then the user_2 is the person who we're going to follow.

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So now let's go ahead and print the user_1's

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follower count and the user_1's following count.

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And let's do the same for user_2 as well.

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You can see once this method has run,

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then user_1's follow account is still zero,

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but user_1 is now following one person.

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User_2 has one followers and has zero people that it's following.

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Right?