title: Fallback callback when calling unavailable function
body: <p>Is it possible to set a fallback callback which is called when the user wants to call a function which does not exists? E.g.</p>
  
  <pre><code>my_object.ThisFunctionDoesNotExists(2, 4);
  </code></pre>
  
  <p>Now I want that a function is getting called where the first parameter is the name and a stack (or something like that) with the arguments passed. To clarify, the fallback callback should be a C++ function.</p>