A Function in Python lets us group code together so that we can reuse it in different places. We have already used in-built functions len() and type() in our previous chapters. Let's create our own function which will calculate the area of a rectangle.
We have declared a function area() above which calculates the area of a rectangle. A function is declared using the def keyword followed by the function name and ():. The next lines contain the statements that will run when this function is called.
To call this function we do area().
