def METHOD_NAME(self, port, vlans):
    if port not in self.baseports:
        self._logger.debug("saw reference to non-existant baseport %s", port)
        return
    # Mark as trunk
    ifindex = self.baseports[port]
    interface = self.containers.factory(ifindex, shadows.Interface)
    interface.trunk = True
    # Store a hex string representation of enabled VLANs
    # in swportallowedvlan
    allowed = self.containers.factory(ifindex, shadows.SwPortAllowedVlan)
    allowed.interface = interface
    allowed.hex_string = vlan_list_to_hex(vlans)