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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 default_preference_list(self, prefs):
 """Set the default preference list. :param str prefs: A string containing the default preferences for ciphers, digests, and compression algorithms. """

        prefs = _check_preferences(prefs)
        if prefs is not None:
            self._prefs = prefs