->>> list element: +relay_domains
->>> list element: @mx_any
->>> d in "@mx_any"? no (end of list)
+>>> d in "+relay_domains"?
+>>> list element: +relay_domains
+>>> start sublist relay_domains
+>>> d in "@mx_any"?
+>>> ╎list element: @mx_any
+>>> ╎check dnssec require list
+>>> ╎check dnssec request list
+>>> d in "@mx_any"? no (end of list)
+>>> end sublist relay_domains