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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 is_opus_maximum(self):
 """Check whether the work is the author's opus maximum. Two cases: 1. the work is flagged as opus max 2. there is only one work by this author :return: boolean """

        opmax = self._get_opus_maximum()
        types = self.ecrm_P2_has_type

        if opmax in types:
            return True
        else:
            if len(self.author.get_works()) == 1:
                return True
            else:
                return False