diff --git a/src/leaf_data_type.cpp b/src/leaf_data_type.cpp
index 815d0aa..8048efa 100644
--- a/src/leaf_data_type.cpp
+++ b/src/leaf_data_type.cpp
@@ -39,6 +39,10 @@
 {
     return this->m_targetXPath == other.m_targetXPath && *this->m_targetType == *other.m_targetType;
 }
+bool Union::operator==(const Union& other) const
+{
+    return this->m_unionTypes == other.m_unionTypes;
+}
 bool String::operator==(const String&) const
 {
     return true;