Quiz: Crashes

#!/usr/bin/python
def calculate_average(numbers):
    total = sum(numbers)
    average = total / len(numbers)
    return average
def main():
    values = [1, 2, 3, 5]
    values.append("6")
    average = calculate_average(values)
    print("Average:", average)
if __name__ == "__main__":
    main()