import com.subgraph.orchid.crypto.TorSignature.DigestAlgorithm; //导入依赖的package包/类
void addSignature(DirectorySignature signature) {
	final VoteAuthorityEntry voteAuthority = voteAuthorityEntries.get(signature.getIdentityDigest());
	if(voteAuthority == null) {
		logger.warning("Consensus contains signature for source not declared in authority section: "+ signature.getIdentityDigest());
		return;
	}
	final List<DirectorySignature> signatures = voteAuthority.getSignatures();
	final DigestAlgorithm newSignatureAlgorithm = signature.getSignature().getDigestAlgorithm();
	for(DirectorySignature sig: signatures) {
		DigestAlgorithm algo = sig.getSignature().getDigestAlgorithm();
		if(algo.equals(newSignatureAlgorithm)) {
			logger.warning("Consensus contains two or more signatures for same source with same algorithm");
			return;
		}
	}
	signatureCount += 1;
	signatures.add(signature);
}