I have some questions about 'Data Consistency'

[LiJie20190102]

What does this line of code mean? I don't quite understand. I haven't tested any consistency check errors

`
@test
public void testUnique(){
JanusGraph graph = ConfiguredGraphFactory.open(GRAPH_NAME);

  JanusGraphManagement mgmt = graph.openManagement();
  PropertyKey name;
  if ((name = mgmt.getPropertyKey("consistentName")) == null) {
      name = mgmt.makePropertyKey("consistentName").dataType(String.class).make();
  }
  mgmt.setConsistency(name, ConsistencyModifier.LOCK); // Ensures only one name per vertex


  VertexLabel unique_test11 = mgmt.getVertexLabel("unique_test11");
  if (Objects.isNull(unique_test11)) {
      unique_test11 = mgmt.makeVertexLabel("unique_test11").make();
      mgmt.addProperties(unique_test11, name);
  }

  mgmt.commit();

  JanusGraphTransaction tx = graph.buildTransaction().checkExternalVertexExistence(false).start();
  tx.addVertex(T.id, "test1", T.label, "unique_test11", "consistentName", "aaa");
  tx.addVertex(T.id, "test2", T.label, "unique_test11", "consistentName", "aaa");
  tx.commit();

}
`

[li-boxuan]

mgmt.setConsistency(name, ConsistencyModifier.LOCK); // Ensures only one name per vertex

So that no two transactions can modify the name at the same time.