code: protected PlacementConfig verifyAndUpdatePlacement(final String alias, final PlacementConfig placementConfig) throws CouldNotPerformException, EntryModification {
          try {
              if (alias == null || alias.isEmpty()) {
                  throw new NotAvailableException("label");
              }
  
              if (placementConfig == null) {
                  throw new NotAvailableException("placementconfig");
              }
  
              String frameId = generateFrameId(alias, placementConfig);
  
              // verify and update frame id
              if (placementConfig.getTransformationFrameId().equals(frameId)) {
                  return null;
  
              }
              return placementConfig.toBuilder().setTransformationFrameId(frameId).build();
          } catch (CouldNotPerformException ex) {
              throw new CouldNotPerformException("Could not verify and update placement!", ex);
          }
      }
docs: Methods verifies and updates the transformation frame id for the given placement configuration.
  If the given placement configuration is up to date this the method returns null.
  
  @param alias
  @param placementConfig
  @return
  @throws CouldNotPerformException
  @throws EntryModification