Add info about default values to describe

Change-Id: I9919e0d366b56ac17e7b606aa5aa0ae048b447c3
diff --git a/src/static_schema.cpp b/src/static_schema.cpp
index 50a6370..dfb12e8 100644
--- a/src/static_schema.cpp
+++ b/src/static_schema.cpp
@@ -221,3 +221,8 @@
 {
     throw std::runtime_error{"Internal error: StaticSchema::isConfigLeaf(std::string) not implemented. The tests should not have called this overload."};
 }
+
+std::optional<std::string> StaticSchema::defaultValue([[maybe_unused]] const std::string& leafPath) const
+{
+    throw std::runtime_error{"Internal error: StaticSchema::defaultValue(std::string) not implemented. The tests should not have called this overload."};
+}