code: def update_nexusport_binding(port_id, new_vlan_id):
      
      if not new_vlan_id:
          LOG.warning("update_nexusport_binding called with no vlan")
          return
      LOG.debug("update_nexusport_binding called")
      session = bc.get_writer_session()
      binding = _lookup_one_nexus_binding(session=session, port_id=port_id)
      binding.vlan_id = new_vlan_id
      session.merge(binding)
      session.flush()
      return binding
docs: Updates nexusport binding.