Examine this Observer pattern code snippet. What is the issue with the notifyObservers method?

Examine this Observer pattern code snippet. What is the issue with the notifyObservers method?

class Subject:
    def __init__(self):
        self.observers = []
    def addObserver(self, observer):
        self.observers.append(observer)
    def notifyObservers(self):
        for observer in self.observers:
            observer.update()