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- [Instructor] Hi and welcome back.

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We are now at the @classmethod

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and @staticmethod coding exercise.

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This one is a bit more
of a complicated one.

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We have to complete two
method implementations.

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The franchise method, which
takes in a store as an argument,

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and it should return a new store object

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with a name equal to the argument
plus the franchise string.

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And the store_details method

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which also takes in a store as an argument

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and it should return a string

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representing the argument.

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Okay, let's have a wee look
at exactly what this means.

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I've given you a few examples here

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of what exactly should be printed out.

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Imagine we have two stores.

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Store is a store with name Test

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and store2 is a store with name Amazon

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and in store2 we're gonna add an item,

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Keyboard with a price of 160.

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The franchise method is
gonna be called as the store,

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the class store.franchise

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and we're gonna pass in the store object

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and it's going to return a store object

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with name Test - Franchise.

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And similarly we call it with
store2 which is called Amazon.

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We're gonna return a store object

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with name Amazon - Franchise.

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So notice it's not going to return

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the string Amazon - Franchise.

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It's going to return a store object

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with name Amazon - Franchise.

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And the store_details is
gonna be called with a store

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so store test

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and is going to return
Test, the name of the store,

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comma, total stock price is zero.

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And similarly if we call it
with store2 which has an item

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it's gonna be Amazon,
total stock price is 160.

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Okay?

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When completing the store_details method

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you may need to convert the output

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of store.stock_price to an integer

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and you can do this like so,

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int(Store.stock_price).

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Let's have a look at this coding exercise.

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First thing to do is to remind ourselves

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of exactly what these existing methods do

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and what the store objects are like.

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So we've got an init method

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that tells us the store
object has two properties:

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self.name and self.items.

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We can add an item which simply
appends to this empty list

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a dictionary with name and price.

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And then we have stock_price
which returns the total value

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of all the items in stock in this store

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as you can see.

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And then we have our two methods

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that we have to implement ourselves:

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the franchise method and
the store_details method.

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The franchise method has
to return another store

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with the same name as the argument

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plus the string " - Franchise."

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So let's do that.

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How do we create a store object?

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Well we can say something
like new_store = Store

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and here we have to give it a name

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because if you remember, the
init method takes in a name

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so we have to give the store this name

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and we know from the instructions

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that the store's name that we return

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has to be the same name as the argument

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so store.name

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plus this "- Franchise" thing here

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so " - Franchise."

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Notice that there is a
space before the dash

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and there's a space after the dash

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so we have to make sure to
have those there as well.

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This is very important

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or else the code checker
won't be able to deduce

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that you have the right name.

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Okay now that we have created the store

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we can return it.

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Return new_store.

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That's our variable there.

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Of course we could just
skip the variable entirely,

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return the store.

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This is totally fine, same thing.

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Because this is a class method

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we have this cls argument here

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and cls is a reference to the class.

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That's Store by the way.

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So cls is the same thing as Store

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so for the sake of learning

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we can just replace them

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and that means exactly the same thing.

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Let's move on to the store_details.

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This only has to return a string
representing the argument.

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Store is a store object

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and it has to be something in the format

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"NAME, total stock price: TOTAL."

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So I'm gonna copy that

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and what I'm gonna do is return this

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.format(store.name,
int(store.stock_price())).

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Now we have to replace
name for the curly braces

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and total for the curly braces as well.

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Here's what's happening here

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I went a bit quickly there.

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We've got our format string

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which has two sets of curly braces

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and we're gonna go and put
store.name in the first one

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and store.stock_price,

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this is the method that is defined here,

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convert it to an integer,

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and put it in the second place there.

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There are many other ways
that you could do this.

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You could add the values
together and so on and so forth

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but, nevertheless, this is the way I do it

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so that's why I'm showing it to you here.

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Let's check our solution

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and as you can see that is all correct.

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We've looked at the cls keyword

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and we've implemented the franchise method

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to return a new store with a given name

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and we've also looked at
the store_details method

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which returns a string representation

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of some store data.

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So that's everything for this video

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and I'll see you on the next one.