{% load i18n %}
{% if not sub.lesson_period.lesson.subject and not sub.subject %}
{% elif sub.cancelled or sub.cancelled_for_teachers %}
{{ sub.lesson_period.lesson.subject.abbrev }}
{% elif sub.subject and sub.lesson_period.lesson.subject %}
{{ sub.lesson_period.lesson.subject.abbrev }}
→
{{ sub.subject.abbrev }}
{% elif sub.subject and not sub.lesson_period.lesson.subject %}
{{ sub.subject.abbrev }}
{% else %}
{{ sub.lesson_period.lesson.subject.abbrev }}
{% endif %}