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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 _get_opus_maximum(self):
 """Instantiate an opus maximum type."""

        label = """The opux maximum of a given author
                    that is, the only preserved work by that
                    author or the most known one."""

        opmax = self.session.get_resource(
            BASE_URI_TYPES % "opmax",
            self.session.get_class(surf.ns.ECRM['E55_Type'])
        )
        if opmax.is_present():
            return opmax
        else:
            opmax.rdfs_label.append(Literal(label, "en"))
            logger.debug("Created a new opus maximum type instance")
            opmax.save()
            return opmax