+ Sequential_music * seq = dynamic_cast<Sequential_music*> (rp->body ());
+ sequential_body_b_ = seq;
+
+ int elt_count = seq ? scm_ilength (seq-> music_list ()) : 1;
+
+ if (seq && elt_count != 2)
+ {
+ rp->origin ()->warning (_f ("Chord tremolo with %d elements. Must have two elements.", elt_count));
+ }
+
+ if (elt_count <= 0)
+ elt_count = 1;
+