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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 set_default_mode(self, default_mode):
 """Set the default mode when alarms are turned 'on'."""

        if default_mode.lower() not in (CONST.MODE_AWAY, CONST.MODE_HOME):
            raise AbodeException(ERROR.INVALID_DEFAULT_ALARM_MODE)

        self._default_alarm_mode = default_mode.lower()