diff --git a/Function.hpp b/Function.hpp
index cda354b..5fc6299 100644
--- a/Function.hpp
+++ b/Function.hpp
@@ -5,5 +5,11 @@ class Function;
 template <typename Ret, typename... Args>
 class function
 {
-    // TODO: everything :'D
+private:
+    class callable_base
+    {
+    public:
+        virtual Ret call(Args...) = 0;
+    };
+public:
 };
\ No newline at end of file