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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 description(self):
 """string or None if unknown"""


        name = None
        try:
            name = self._TYPE_NAMES[self.audioObjectType]
        except IndexError:
            pass
        if name is None:
            return
        if self.sbrPresentFlag == 1:
            name += "+SBR"
        if self.psPresentFlag == 1:
            name += "+PS"
        return text_type(name)