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You actually already know how to write a simple Python script and store it in a file and then execute

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it to streamline you in the previous lecture.

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We've got a file that contains a program that simply makes the lid on Tiberio.

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Twenty one to blink.

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There's not really much more to it.

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But in this lecture, I want to show you an example of how you can split your Python programs into multiple

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parts so that you can better organize your code, which is particularly useful as your programs become

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more complicated and larger.

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So can you click on Stop to interrupt the execution of the program?

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The LTTE has stopped blinking.

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And let's have a look at these two files, which I have stored on the device itself.

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The first one is called Arithmetic, and it just contains two functions.

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The first one adds two numbers.

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The second one subtracts them.

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Now, this is the function name and the two parameters.

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And again, don't worry about this.

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I've got a whole section on Python.

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And so the basic Python primer to help you get started with these Python concepts and how to create

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functions and classes and how to format your numbers and your output messages.

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All this is in Section five, the next one for now, as usual.

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Just go along with this.

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So this file contains the two functions.

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Each function is organized in the same way I've got a print statement and usually format function and

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a couple of placeholders here.

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Three placeholders to print out the numbers that participate in this calculation.

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And the result is just an automatic calculation.

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Nothing fancy now in this program here.

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And I use underscore arithmetic to why the first thing that I do is to use the import statement or Keywood

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to import the let's call it a library, a little library that has two functions in it.

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And to do that, I need to use the name of the file without the extension.

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So here's the name of the file arithmetic to try to import it.

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I just use the name of the file without the extension arithmetic.

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And now I'm able to use these two functions in my use arithmetic program.

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So I start by creating the two variables and initialize them with a couple of numbers that I came up

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with.

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And then I'm calling the add numbers that belong to the arithmetic library and I pass the two required

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parameters, number one and number two.

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And you can see when I run this program by clicking on the button, it just works.

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So, of course, these two programs are tiny.

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But imagine now that they become much bigger.

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The ability to split them into multiple files means that each one of those files is going to be dedicated

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to specific purpose and it's going to be simpler to both write and to maintain.

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There's a few more things that I want to show you in this section, in the next lecture, I'm going

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to show you how to interrupt the running program and then how to set a program to automatically execute

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at boot time.

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And finally, how to do a bit of debugging on the phone idea for your micro python program, because

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remember, you don't really have all of the amazing tools that come with the only available to see Python.