async def METHOD_NAME(self, event_source_id, ttl) -> Optional[EventSource]:
    """
    Event source cache
    """
    if ttl > 0:
        return await MemoryCache.cache(
            self.event_source_cache(),
            event_source_id,
            ttl,
            event_source_db.load,
            True,
            event_source_id
        )
    return await event_source_db.load(event_source_id)