[igraph] igraph_isohandler_t: whose responsibility is to free map12 and map21?

[Szabolcs Horvát]

Dear All,

The  igraph_isomorphic_function_vf2()  function takes a callback of the type

typedef igraph_bool_t igraph_isohandler_t(const igraph_vector_t
*map12, const igraph_vector_t *map21, void *arg);

Whose responsibility is it to igraph_vector_destroy() map12 and map21?
  Does it need to be done in the handler or does
igraph_isomorphic_function_vf2() do it?

I am hoping and assuming that it is left to the handler, but I would
like to make sure.

Szabolcs