private SignatureObject getSubChunkSignature() {
        // In current, it has no idea about how to compute the signature for sub chunk.
        throw new NotImplementedException("The Get sub chunk signature method is not implemented.");
    }
Get the signature for sub chunk.

@return An instance of SignatureObject.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/onenote/fsshttpb/streamobj/chunking/ZipFilesChunking.java