Средний балл

def average(marks):
    if not marks:
        return 
    res = sum(marks) / len(marks)
    result = round(res, 5)
    print(result)
    return result

def average(marks):
    res = sum(marks) / len(marks)
    result = round(res, 5)
    print(result)
 
marks = [5, 4, 3, 4]
average(marks)

def average(marks):
    res = sum(marks) / len(marks)
    result = f"{res:.5f}"
    print(result)
 
 
marks = [5, 4, 3, 4]
average(marks)

def average(marks):
    if marks:
        result = sum(marks) / len(marks)
        return round(result, 5)
    return None

def average(marks):
    if len(marks) == 0:
        return None
    
    # вычисляем среднее арифметическое
    avg = sum(marks) / len(marks)
    
    # округляем до пяти десятичных знаков
    rounded_avg = round(avg, 5)
    
    return rounded_avg

def average(marks):
    if not marks:
        return None
    result = round(sum(marks) / len(marks), 5)
    print(result)
    return result