fromdatetimeimportdatetimefromgroupdocs.signatureimportSignaturefromgroupdocs.signature.optionsimportMetadataSignOptionsfromgroupdocs.signature.domainimportPdfMetadataSignatureswithSignature("sample.pdf")assignature:options=MetadataSignOptions()# Clone a metadata signature with a new valueauthor_sig=PdfMetadataSignatures.AUTHOR.clone("Mr. Sherlock Holmes")options.signatures.add(author_sig)