Using a custom vertex id

How to use a custom vertex id in queries.

Vertices can be filtered using a hasId() traversal step and providing a particular custom vertex id.
g.V().hasId(['~label':'FridgeSensor','city_id':100,'sensor_id':'60bcae02-f6e5-11e5-9ce9-5e5517507c66']).valueMap()
A vertex can be queried directly using a custom vertex id.
g.V(['~label':'FridgeSensor','city_id':100,'sensor_id':'60bcae02-f6e5-11e5-9ce9-5e5517507c66']).valueMap()