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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_parent(self) -> Optional['CentralDogma']: """Get the parent, or none if it's already a reference node. :rtype: Optional[CentralDogma] Example usage: """

        if VARIANTS not in self:
            return

        return self.__class__(namespace=self.namespace, name=self.name, identifier=self.identifier)