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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 activate_next(self, _previous=False):
 """ Activate next value. """

        current = self.get_current_value()
        options = sorted(self.values.keys())

        # Get current index.
        try:
            index = options.index(current)
        except ValueError:
            index = 0

        # Go to previous/next index.
        if _previous:
            index -= 1
        else:
            index += 1

        # Call handler for this option.
        next_option = options[index % len(options)]
        self.values[next_option]()