Make set report the expected type in case of error

Change-Id: Id46251b4859739e3c8f77d3bf2513ec22b048cf1
diff --git a/src/utils.hpp b/src/utils.hpp
index 2c550d7..9583ebe 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -7,7 +7,9 @@
 */
 #include <string>
 #include "ast_path.hpp"
+#include "schema.hpp"
 
 std::string joinPaths(const std::string& prefix, const std::string& suffix);
 std::string stripLastNodeFromPath(const std::string& path);
 path_ pathWithoutLastNode(const path_& path);
+std::string leafDataTypeToString(yang::LeafDataTypes type);