code: private static JsonNode getFsLayers(JsonNode manifest, boolean isSchemeVersion1) {
          JsonNode fsLayers;
          if (isSchemeVersion1) {
              fsLayers = manifest.get("fsLayers");
          } else {
              fsLayers = manifest.get("layers");
          }
  
          if (fsLayers == null) {
              throw new IllegalStateException("Could not find 'fsLayers' or 'layers' in manifest");
          }
          return fsLayers;
      }
docs: Return blob sum depend on scheme version.
  
  @param manifest
  @param isSchemeVersion1
  @return