wrong name for function in part 12 description of exercise 13 part 3

[wolfing]

The description in third part of exercise 13 in part 12 asks to add a function "average_grade" but when doing the testing and submission it is requiring the function to be named "average". Either change the tests to use "average_grade" or change description to name the function "average".

[jussmaki]

Fixed. Thank you! :)