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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 history_add(self, value):
 """Add a value in the history """

        if self._history_max_size is None or self.history_len() < self._history_max_size:
            self._history.append(value)
        else:
            self._history = self._history[1:] + [value]