 Hi again. In this lesson, we are going to talk about annotations and why and how you should use annotations in Python programming language. If someone wants to use your code, it will be easier for him if you've provided documentation. Annotations are a document standard. Python 3 supports annotations. They are optional and they give to us informations how to use that code. Let's make a simple function and let's add annotations to it. We want to give a user of our function info about what that function does and what the arguments and return value are going to be. Let's make some simple function. For example, let's define function multiply by 5. We are going to multiply any number that is given to us as an argument of this function. So we want to get some number as an argument and let's say that it has integer type with colon sign and int. This kind of additional information that we are providing is annotation. So we are going to inform users of our function that the argument of our function is integer and now we also want to give information that returning value will be also integer. So on that way, when we are writing this code, we are giving to our users of our function that returning value will be int. Let's say that we want to return that same number multiplied by 5. Okay, but before we are going to do that, let's give to our users some additional information about what our function does. We'll put our description of our function inside triple quotes. Let's say this function returns number multiplied by 5. Okay, and let's return our number multiplied by 5 and that's our function. Let's check if it does work. Multiply by 5, for example, number 4 and we get result 20, so 5 times 4 equals 20. How we can use our information or better say that we provide it to our function, that user can further use them to see what function does and what are the arguments and return value of this function. If we call function help and inside as an argument of this function we put our function, we'll get information that our function needs integer number as argument and it returns integer number and what this function does, this function returns number multiplied by 5. So this annotations really helps to users of our function to use our functions further in coding. That's all for this lesson, thanks for watching.