'Return the list of courses which use this wiki_slug
:param wiki_slug: the course wiki root slug
:return: list of course keys'

def get_courses_for_wiki(self, wiki_slug, **kwargs):

    courses = self.collection.find({'_id.category': 'course', 'definition.data.wiki_slug': wiki_slug}, {'_id': True})
    return [Location._from_deprecated_son(course['_id'], course['_id']['name']).course_key for course in courses]
