1 files changed, 2 insertions, 2 deletions
diff --git a/src/pkl.h b/src/pkl.h
index aa78ae21..bc71279e 100644
--- a/src/pkl.h
+++ b/src/pkl.h
@@ -60,8 +60,8 @@ public:
 		return _standard;
 	}
 
-	std::string hash (std::string id) const;
-	std::string type (std::string id) const;
+	boost::optional<std::string> hash (std::string id) const;
+	boost::optional<std::string> type (std::string id) const;
 
 	void add_asset (std::string id, boost::optional<std::string> annotation_text, std::string hash, int64_t size, std::string type);
 	void write (boost::filesystem::path file, boost::shared_ptr<const CertificateChain> signer) const;