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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 resize(self, flavor):
 """Set the size of this instance to a different flavor."""

        # We need the flavorRef, not the flavor or size.
        flavorRef = self.manager.api._get_flavor_ref(flavor)
        body = {"flavorRef": flavorRef}
        self.manager.action(self, "resize", body=body)