'Generate a pymongo in query for finding the items and return the payloads'

@autoretry_read()
def _query_children_for_cache_children(self, course_key, items):

    query = {'_id': {'$in': [course_key.make_usage_key_from_deprecated_string(item).to_deprecated_son() for item in items]}}
    return list(self.collection.find(query))
