The average test grade can be found by dividing the sum of the grades by the total number of grades.
Luckily, we just created an awesome function, grades_sum to compute the sum.
Define a function, grades_average, below the grades_sum function that does the following:
grades_input, a listgrades_sum with grades_inputfloat(len(grades_input)).Call the newly created grades_average function with the list of grades and print the result.