+=head2 addHours
+
+ my $dt = $calendar->addHours($date, $dur, $return_by_hour )
+
+C<$date> is a DateTime object representing the starting date of the interval.
+
+C<$offset> is a DateTime::Duration to add to it
+
+C<$return_by_hour> is an integer value representing the opening hour for the branch
+
+
+=head2 addDays
+
+ my $dt = $calendar->addDays($date, $dur)
+
+C<$date> is a DateTime object representing the starting date of the interval.
+
+C<$offset> is a DateTime::Duration to add to it
+
+C<$unit> is a string value 'days' or 'hours' toflag granularity of duration
+
+Currently unit is only used to invoke Staffs return Monday at 10 am rule this
+parameter will be removed when issuingrules properly cope with that
+
+