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Hi, everybody.

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All right, so now that we are past theri level basics regarding methods and we have seen in the previous

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video how to create simple methods and also how to create methods that receive variables from the execution

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level, I think it's time to get over to the mid level theory and see some more cool tricks that methods

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can apply on.

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Also, you can see here behaviors, some of them, those are especially only in Python as Python is

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a very flexible language.

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And it can see really, really cool tricks here that other programming languages cannot do.

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All right.

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So let's start off with the first one and let's just go over it.

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All right.

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So we have seen that we can pass variables into methods, but what if we're not sure that each time

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that a certain method would be called out would be executed?

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We're not sure that each time we will have a variable to pass through it.

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OK, so in this case, we'll have simply an error because like, if a certain method should receive

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a variable and we can see it in the declaration level with the line that contains the def keyword and

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it should get a variable BOBERT from the module level, we did not pass a variable.

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So this will cause all program to to fail.

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But for that we have a solution in Python.

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All right.

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So in this case that we are not sure if certain variable variable will be passed to a method.

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You can see the example right here.

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We can do the following thing.

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We can set a default value to the method, meaning right here we can see that we have created my function.

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All right.

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This is the method.

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And inside the round brackets, we have set a value country equals Canada.

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All right.

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So this is the declaration.

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And from here, from the middle part here, we're going to execute the execute the the method and let's

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see what happens.

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So if we take the method and execute it for for the first one right here, we're seeing my function.

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And then inside the brackets we see Eataly.

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So the printout inside the method would be, I'm from Italy.

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That's easy.

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But from the green one right here, we can see that we haven't passed any variable to this method at

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all.

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All right.

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So it's empty.

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We have some kind of problem here because the print here is waiting for a variable.

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And we did not pass any variable to this method.

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But we have overcame this of failure with the following solution.

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We have set a default value for this method right here in the in the declaration line.

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So you can see contre equals Canada, meaning that once we will not have any value set up here in the

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execution level, the different value, the default value that would be printed out here would be Canada.

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So this is how we can now overcome an exception or an error in the side, our code execution by setting

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up a default value.

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All right, let's go straight ahead to the next topic that we're going to learn regarding methods,

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and it goes as follows.

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OK, so we already familiar that methods can receive variables, all collections into them in the execution

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line.

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But a method can also return a value back to the module level, meaning that if we would like to pass

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some variable out of the method into the module level, we can achieve it.

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OK, so here we have again, we have a declaration of a module.

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OK, my function and you can see here the new keyword that we're not familiar with up until this point

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return can see it marked in pink.

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I saw the return key word basically returns, whatever comes after it into the execution level that

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we can see right here with a pink and recombined.

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OK, so first of all, we execute the we execute the method by stating its name right here, my function,

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and we're passing the variable three into it.

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OK, so from here it goes up to the top and X equals three, meaning it goes inside and inside we can

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see a return five equals X, right.

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And in this case, X is equals three.

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So basically a return will be would be returned the value of 15 in our case.

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So what am I doing here is once I executed the method right here, I put an equal sign to the left and

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to the left some more.

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I've created a new variable called number, and as this method right here returns a value.

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OK, so this number variable would get this value that was extracted out of the method to the module

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level right here outside of the method.

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This is the module level and here with the intention is the method level.

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So right here in the module level, we would get the value that was returned from inside the method

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to out here and then we can do whatever we want with it.

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In our case, the value that was set inside the method is three three three multiplied by five is 15.

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So once we print this number variable, we would get the output 15, correct.

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I would like to do the following thing, which is going to copy all of this code.

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OK.

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And show it to you live on by charm, I think is the best way to understand things like that.

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All right.

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OK, so here's the method and here's the return.

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So basically from here, the three goes up in here to the X, OK?

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And then this X goes inside the method right here.

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And we have the return, as you can see.

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Also, the return is is with orange color, which is a special keyword.

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And then after the return, we have five multiplied by three in our case.

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OK, and then the number of variable right here gets whatever comes out of this method.

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This is like we have a return from here.

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So everything that is returned from here goes straight to this number.

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So as you can see, when we run it, we get the output 15 in once we delete it.

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For example, let's put it in.

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The comments on this line does not exist and let's put base here so we won't have any error.

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And now once we will run it, we will get nothing.

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All right.

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We have none because number was never set up with anything, because here we didn't have any return

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action made out from inside of the method.

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So we have none here.

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But when we have this value, the value that comes after the return is being returned to the execution

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level and we can straight set up a variable and print it out.

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And we also can do the following thing.

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We can just take this thing, which equals 15 and also put this one inside here inside the print, because

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this whole term equals to 15 once we print it.

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OK, so there you go.

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So we don't even need the number available.

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Just easier to understand with.

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No.

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So, OK, in this case, the number gets the value for whatever comes from here.

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All right.

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And for the first example right here, I also want to show it.

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Let me just copy it to them, to the picture and let's look at it together.

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OK, so right here we have this thing.

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I'm just going to delete the output, OK?

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And just going to leave the EU one with a variable passed to the method and one without with an empty,

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empty one.

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All right.

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And once we execute it, so you see it runs perfectly because in the second case, once we did not pass

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that variable to the method.

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OK, so the default value was executed and this country equals Canada was set up in here and we have

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it inside the printout.

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What if we will remove this one?

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All right.

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Just just leave country here.

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You see that right here.

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If we hover above above it, parameter country on field.

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OK, so we have a certain problem here.

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And you see we have an exception.

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It's a fail, by the way, just reminding that we are going to learn all of these type errors and exceptions

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in a later stage.

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But for now, we're just seeing that we have a problem here regarding this execution right here, because

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at certain value is expected of the method to be inserted in here.

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But nothing comes in.

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And then we have a problem because the the code does not know what to run here.

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So if we have the default value, we do not have any issues with this thing.

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All right.

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That's about it.

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Regarding Python mid-level lecture, regarding methods, I think we're done with this one.

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I'll see you in the next lecture where where we discuss some.

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Furthermore, regarding methods, this will be the advanced lecture.

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Thank you and bye bye.