Define Test as custom
  function showString(aString)
    ? aString
  endfunc
Enddefine

Define Test1 as Test
  function showString(aString)
    <b>dodefault</b>(this.fixFunc(aString))
  endfunc
  function fixFunc(aString)
    <b>return 'String: ' + aString</b>
  endfunc
Enddefine

<b>Define Test2 as Test1
Enddefine</b>