diff --git a/calendar/generate_calendar.php b/calendar/generate_calendar.php
index 3b341f4..fcd5aa2 100755
--- a/calendar/generate_calendar.php
+++ b/calendar/generate_calendar.php
@@ -33,7 +33,7 @@
 					break week falls after the sixth then that week is week
 					number 7. The numbering of teaching weeks will skip the
 					break weeks regardless. If there are no breaks in the
-					period, then set this to null.
+					period, then set this to an empty array.
 					
 					Note that we aren't clever about coalescing contiguous
 					weeks. For example, if weeks 7 and 8 are indicated as break
@@ -45,7 +45,7 @@
 	'SummerSchool' => array(
 		'start_date'  => new DateTime( "2012-01-09" ),
 		'num_weeks'   => 6,
-		'break_weeks' => null,
+		'break_weeks' => array(),
 	),
 	'SemesterOne' => array(
 		'start_date'  => new DateTime( "2012-02-27" ),