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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_or_update(self, section, key, value):
 """Update the key or, if no previous value existed, add it. Returns: int: Number of updated lines. """

        updates = self.update(section, key, value)
        if updates == 0:
            self.add(section, key, value)
        return updates