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Oh boy there's some code on the screen and it looks terribly confusing.

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This is an example of a really convoluted complicated function that you would never write but it'll

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be good for exercise purposes.

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And we're talking specifically about this right here called non local.

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It's actually a new keyword in Python 3.

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And as you can see my ripple doesn't even notice it so it doesn't even highlighted in blue because it

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is a new feature.

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But I do want to talk to you about it and let you know what it does the non local keyword is used to

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refer to this part.

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This parent local it's a way for us to say hey I want to use a variable that is not a global variable

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but is outside of the scope of my function so based on that definition try and pause the video and see

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what this function might do.

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I'll run it right now and then go through the code if I click Run.

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This is what we get so let's talk about this.

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We have an outer function and then we call the outer function.

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So the Python interpreter is going to go and say All right we have an x variable that is local to the

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outer function and then inside of here we're going to define an inner function.

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Another function and then here before we even call that we jumped in line nine and say All right call

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inter function.

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We come back and we say hey line five I want to use non local x.

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What does that mean.

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Well I want to use this x variable because it's non local.

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That is I don't want to create a new x variable.

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I want to jump up the scope to my parents scope my parent local and grab whatever you find in there

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as long as it's not global variable.

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Any parent will do.

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I want to grab that non-local.

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So now this ex is referring to the outer function here.

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So when we say X equals non-local we're assigning this new string and replacing this local so that when

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we print inner x we get non-local but also when we print the outer X we've modified this outer scope

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with the non-local keyword.

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So that becomes non local as well.

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If I remove this line and let's comment it out and I click Run you see the difference.

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Now we have the inner non-local but then the outer local hasn't been modified because this is a new

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variable.

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Again I argue that this actually makes your code more complicated than it needs to be.

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So there are special cases where you might want to use this but if you can try to make your code predictable

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where you can avoid using things like non-local and global mind you they are there for a reason because

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they are useful in some situation.

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With that said keep in mind make your code predictable make your code clean and I'll see you in the

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next video.