moving_average.py

class MovingAverage:
    total_sum = 0
    total_count = 0
    
    def add_number(self, num):
        self.total_sum += num
        self.total_count += 1
    
    def get_average(self):
        return self.total_sum / self.total_count
    
    def reset(self):
        self.total_sum = 0
        self.total_count = 0

ma = MovingAverage()
ma.add_number(5)
ma.add_number(10)
# ... etc
ma.get_average()

This isn't really a moving average though - same could be achieved with (psudo code, I don't know python)

class MovingAverage:
    average = None

    def add_number(self, num):
        if self.average is None:
            self.average = num
        else:
            self.average = (self.average + num) / 2

    def get_average(self):
        return self.average

    def reset(self):
        self.average = None

In this case not really worthy of a class...