diff --git a/src/utils.cpp b/src/utils.cpp
index 979bda4..672cd36 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -113,6 +113,14 @@
         return data;
     }
 
+    std::string operator()(const bool& data) const
+    {
+        if (data)
+            return "true";
+        else
+            return "false";
+    }
+
     template <typename T>
     std::string operator()(const T& data) const
     {