1 files changed, 1 insertions, 0 deletions
diff --git a/src/xml.h b/src/xml.h
index 65eb7399..9b600013 100644
--- a/src/xml.h
+++ b/src/xml.h
@@ -38,6 +38,7 @@ protected:
 	Time time_attribute (std::string);
 	float float_attribute (std::string);
 	std::string string_attribute (std::string);
+	std::string optional_string_attribute (std::string);
 	int64_t int64_attribute (std::string);
 	int64_t optional_int64_attribute (std::string);
 	boost::optional<bool> optional_bool_attribute (std::string);