update privious livelessons list

apps/school/templates/blocks/schedule_purchased.html

@@ -38,7 +38,9 @@
             {% else %}
             {% for school_schedule in school_schedules %}
             {% if is_previous %}
+            {% if school_schedule.previous_live_lesson  %}
             {% include './_schedule_purchased_item.html' with school_schedule=school_schedule live_lesson=school_schedule.previous_live_lesson %}
+            {% endif %}
             {% else %}
             {% include './_schedule_purchased_item.html' with school_schedule=school_schedule live_lesson=school_schedule.current_live_lesson %}
             {% endif %}