Problem with cmods

Hi, i have a little problem with cmods. i write

--SNIP--
PIKECLASS PikeTest{
  PIKEFUN string func(string mystring){
    struct pike_string *foo = make_shared_string("foo");
    pop_n_elems(args);
    push_string(foo);
  }
}
--SNIP--

it compiles without problems but if i try to call these function like

write(PikeTest.func("foo"));

i get the message "Index 'func' not present in module 'PikeTest'"

whats wrong with my code?

Best regards & thx for help
-Chris