docs: def port_create_vlan(br, port, id, internal=False):
      '''
      Isolate VM traffic using VLANs.
  
      Args:
          br: A string - bridge name.
          port: A string - port name.
          id: An integer in the valid range 0 to 4095 (inclusive), name of VLAN.
          internal: A boolean to create an internal interface if one does not exist.
  
      Returns:
          True on success, else False.
  
      .. versionadded:: 2016.3.0
  
      CLI Example:
      .. code-block:: bash
  
         salt '*' openvswitch.port_create_vlan br0 tap0 100
      '''
      interfaces = __salt__['network.interfaces']()
      if not 0 <= id <= 4095:
          return False
      elif not bridge_exists(br):
          return False
      elif not internal and port not in interfaces:
          return False
      elif port in port_list(br):
          cmd = 'ovs-vsctl set port {0} tag={1}'.format(port, id)
          if internal:
              cmd += ' -- set interface {0} type=internal'.format(port)
          result = __salt__['cmd.run_all'](cmd)
          return _retcode_to_bool(result['retcode'])
      else:
          cmd = 'ovs-vsctl add-port {0} {1} tag={2}'.format(br, port, id)
          if internal:
              cmd += ' -- set interface {0} type=internal'.format(port)
          result = __salt__['cmd.run_all'](cmd)
          return _retcode_to_bool(result['retcode'])