# GPACalc.py
# Demonstrate assertions in Python
# if the expression is false, then an ExceptionError is raised
def GPACalc (ary):
    sum = 0.0
    for f in ary:
        assert f >= 0.0 and f <= 4.3, "Invalid value " + str(f)
        sum += f;
    return sum/len(ary)
    
def main ():
    a = [3.5, 3.8, 4.0, 4.1, 4.5]
    print(GPACalc(a))
    
if __name__ == "__main__":
    main()