Calling a method of the same class

This class collects survey scores and calculates their average. It accepts only scores from 1 to 5. Inside average(), the line that calls the class's own total() method stops with an error. Fix one line so that the code prints 4.5. Grading also calls the methods with other scores.

Code to fix

class Survey:
    def __init__(self, question):
        self.question = question
        self.scores = []

    def add(self, score):
        if 1 <= score <= 5:
            self.scores.append(score)

    def total(self):
        result = 0
        for s in self.scores:
            result += s
        return result

    def average(self):
        if len(self.scores) == 0:
            return 0
        return total() / len(self.scores)

s = Survey("Class satisfaction")
s.add(4)
s.add(5)
s.add(9)
print(s.average())