“Initializing” variables in python?

The issue is in the line –

grade_1, grade_2, grade_3, average = 0.0

and

fName, lName, ID, converted_ID = ""

In python, if the left hand side of the assignment operator has multiple variables, python would try to iterate the right hand side that many times and assign each iterated value to each variable sequentially. The variables grade_1, grade_2, grade_3, average need three 0.0 values to assign to each variable.

You may need something like –

grade_1, grade_2, grade_3, average = [0.0 for _ in range(4)]
fName, lName, ID, converted_ID = ["" for _ in range(4)]