diff --git a/src/oatpp-swagger/Model.hpp b/src/oatpp-swagger/Model.hpp
index 543936d..e56bdb5 100644
--- a/src/oatpp-swagger/Model.hpp
+++ b/src/oatpp-swagger/Model.hpp
@@ -577,7 +577,8 @@ class DocumentInfo {
      * @return
      */
     OAuthFlowBuilder& addScope(const String& name, const String& scope){
-      getScopes()->at(name) = scope;
+      //getScopes()->at(name) = scope;
+      getScopes()->operator[](name) = scope;
       return *this;
     }