'Determine the MAC for the DVR port associated to host.'

def get_dvr_mac_address_by_host(self, context, host):

    if (not host):
        return
    try:
        return self._get_dvr_mac_address_by_host(context, host)
    except ext_dvr.DVRMacAddressNotFound:
        return self._create_dvr_mac_address(context, host)
