'Create the trunk.
This patches the bridge for trunk_id with the integration bridge
by means of parent port identified by port_id.
:param trunk_id: ID of the trunk.
:param port_id: ID of the parent port.
:param port_mac: the MAC address of the parent port.
:raises:
TrunkBridgeNotFound: in case trunk bridge does not exist.'

def create_trunk(self, trunk_id, port_id, port_mac):

    trunk = TrunkParentPort(trunk_id, port_id, port_mac)
    try:
        if (not trunk.bridge.exists()):
            raise exc.TrunkBridgeNotFound(bridge=trunk.bridge.br_name)
        trunk.plug(self.br_int)
    except RuntimeError as e:
        raise TrunkManagerError(error=e)
