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[MUSIC]

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Now that the book and patron classes
have been fleshed out a little more,

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let's keep going with the patron
class methods we discussed earlier.

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Check out and return book.

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The check out method is going to
utilize all of the things we did in

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this last stage.

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This method will receive one argument,
a book object.

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What do you think will happen next?

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Well, first we should set
the patron's current book property

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to the book object that was passed in.

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This way,
when a library employee looks up a patron,

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they will see what book, if any,
that patron has checked out.

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Then we can set all the associated
properties on the book object.

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Its out property should be set to true.

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It's patron property should be
set to the patron object itself.

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That can be accomplished by setting
the property to the this keyword.

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This, when used by itself inside a class,
refers to the entire object.

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Finally, the book's dueDate property
should be calculated and set.

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For our purposes, books will be due
two weeks, or 14 days, from checkout.

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The return book method, is basically
the inverse of the check out method.

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The book that's being returned,
is passed in as an argument,

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the patron's current book property
should be set back to null,

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since they're no longer
borrowing the book.

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The book should be marked back in, and

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as a result, its due date property
will be set back to null.

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Then we set the book's patron
property back to null as well.

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I've attached a work space to this video.

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Open it up and
try to code these out on your own.

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There's a read me file inside the work
space with detailed instructions.

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When you're done, or if you get stuck,
head to the next step to see the solution.

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Remember, everything you're
doing is just for practice.