SCM sym = mus->get_mus_property ("symbol");
if (check_grob (mus, sym))
{
SCM eprop = mus->get_mus_property ("grob-property");
SCM sym = mus->get_mus_property ("symbol");
if (check_grob (mus, sym))
{
SCM eprop = mus->get_mus_property ("grob-property");