Let's review the instructions and see where you went wrong...
* First, def a function called cube that takes an argument called number. Don't forget the parentheses and the colon!
* Make that function return the cube of that number (i.e. that number multiplied by itself and multiplied by itself once again).
* Define a second function called by_three that takes an argument called number.
* if that number is divisible by 3, by_three should call cube(number) and return its result. Otherwise, by_three should return False.
Your first function takes care of points 1 and 2. But that's when things begin to break down. See if you can put the code right by following this example pattern:
if number % 3 == 0: # note the % (remainder) operator
Now we need to test our work: