+relative order of the parameters.
+
+Note: This routine assumes neither the passed start_dt nor end_dt can be a closed day
+
+=head2 hours_between
+
+$duration = $calendar->hours_between($start_dt, $end_dt);
+
+Passed two dates returns a DateTime::Duration object measuring the length between them
+ignoring closed days. Always returns a positive number irrespective of the
+relative order of the parameters.
+
+Note: This routine assumes neither the passed start_dt nor end_dt can be a closed day