Retrieves the stats for a hunt.

def _HandleLegacy(self, args, token=None):
    """Retrieves the stats for a hunt."""
    hunt_obj = aff4.FACTORY.Open(
        args.hunt_id.ToURN(), aff4_type=implementation.GRRHunt, token=token)

    stats = hunt_obj.GetRunner().context.usage_stats

    return ApiGetHuntStatsResult(stats=stats)