As you've seen Python has a built-in function called help that will show you information about the function. IDLE will also provide information when you start to type the call on that function. For example, when you call function help on the absolute value function, you get a nice description of what it does. Also, when you start to write a call on that function, it pops a little yellow box in IDLE showing you the type of the parameters and the returned type. You can provide the same kind of information for your own functions by writing documentation in a particular format called a doc strength. We have written documentation for the area of a triangle function that we wrote last week. Notice that we are using a triple coded string because our descriptions spends multiple lines. We will now run this module in order to have area available to us in the Python shell and when I ask for help on area, we now see what we have inside the doc string. Furthermore, this first line of the doc string is what will show up when I start to type a call on area. From now on, we will always provide doc strings for our functions both to describe what they do and also to hook into Python's help system.