diff --git a/include/sdbusplus/asio/object_server.hpp b/include/sdbusplus/asio/object_server.hpp
index 2840373..756f53a 100644
--- a/include/sdbusplus/asio/object_server.hpp
+++ b/include/sdbusplus/asio/object_server.hpp
@@ -105,6 +105,21 @@
 };
 } // namespace details
 
+template <typename InputArgs, typename Callback>
+void callFunction(message_t& m, InputArgs& inputArgs, Callback&& callback)
+{
+    using ResultType = boost::callable_traits::return_type_t<Callback>;
+    if constexpr (std::is_void_v<ResultType>)
+    {
+        std::apply(callback, inputArgs);
+    }
+    else
+    {
+        auto r = std::apply(callback, inputArgs);
+        m.append(r);
+    }
+}
+
 template <typename CallbackType>
 class callback_method_instance : public callback
 {
@@ -118,22 +133,8 @@
   private:
     using CallbackSignature = boost::callable_traits::args_t<CallbackType>;
     using InputTupleType = utility::decay_tuple_t<CallbackSignature>;
-    using ResultType = boost::callable_traits::return_type_t<CallbackType>;
     CallbackType func_;
 
-    void callFunction(message_t& m, InputTupleType& inputArgs)
-    {
-        if constexpr (std::is_void_v<ResultType>)
-        {
-            std::apply(func_, inputArgs);
-        }
-        else
-        {
-            auto r = std::apply(func_, inputArgs);
-            m.append(r);
-        }
-    }
-
     // optional message-first-argument callback
     int expandCall(message_t& m)
     {
@@ -156,7 +157,7 @@
         {
             inputArgs.emplace(dbusArgs);
         }
-        callFunction(ret, *inputArgs);
+        callFunction(ret, *inputArgs, func_);
         ret.method_return();
         return 1;
     }
@@ -210,23 +211,9 @@
   private:
     using CallbackSignature = boost::callable_traits::args_t<CallbackType>;
     using InputTupleType = utility::decay_tuple_t<CallbackSignature>;
-    using ResultType = boost::callable_traits::return_type_t<CallbackType>;
     boost::asio::io_context& io_;
     CallbackType func_;
 
-    void callFunction(message_t& m, InputTupleType& inputArgs)
-    {
-        if constexpr (std::is_void_v<ResultType>)
-        {
-            std::apply(func_, inputArgs);
-        }
-        else
-        {
-            auto r = std::apply(func_, inputArgs);
-            m.append(r);
-        }
-    }
-
     // co-routine body for call
     void expandCall(boost::asio::yield_context yield, message_t& m)
     {
@@ -257,7 +244,7 @@
             inputArgs.emplace(std::tuple_cat(
                 std::forward_as_tuple(std::move(yield)), dbusArgs));
         }
-        callFunction(ret, *inputArgs);
+        callFunction(ret, *inputArgs, func_);
         ret.method_return();
     }
 };