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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 enable(self, interface_id, dns_relay_profile=None):
 """ Enable the DNS Relay service on this engine. :param int interface_id: interface id to enable relay :param str,DNSRelayProfile dns_relay_profile: DNSRelayProfile element or str href :raises EngineCommandFailed: interface not found :raises ElementNotFound: profile not found :return: None """

        if not dns_relay_profile:  # Use default
            href = DNSRelayProfile('Cache Only').href
        else:
            href = element_resolver(dns_relay_profile)

        intf = self.engine.interface.get(interface_id)
        
        self.engine.data.update(dns_relay_profile_ref=href)
        self.engine.data.update(dns_relay_interface=intf.ndi_interfaces)