 Hi everyone. In this lesson, we're going to talk what is the function and why we're using functions in Python. A function is a block of organized reusable code that is used to perform a single specified action. When you're programming in Python sooner or later, you will have a lot of lines of code, maybe 500 or even 1000 lines of code. And that large amount of lines of code quickly became harder to manage. When that happens, it's time to start thinking about reorganizing your code into functions. Python supports modularity so we can break our large amount of code into smaller, more manageable pieces. We're going to do this by creating functions. We can think of a function as named piece of code. Also, we can say that function is something that we can give to it some information, then that function will work with that provided information, maybe change them in some way and finally that function might return to us some new information for work with them further. Python also give us many built-in functions, but we can also create our own functions. These functions are called user defined functions. This is all for this lesson. Thanks for watching. Happy coding!