code: def generate_machine_name(self) -> str:
      while True:
          # 36 ** 5 = ~60M
          suffix = secret_alnum_string(5, case="lower")
          machine_name = f"{self.machine_name_prefix}{suffix}"
          if machine_name not in self.name_instance:
              break
      return machine_name
  
imports: import asyncio
  import collections
  import logging
  import re
  import secrets
  from typing import Any, Counter, Dict, List, Optional, Tuple
  import sortedcontainers
  from gear import Database
  from gear.time_limited_max_size_cache import TimeLimitedMaxSizeCache
  from hailtop import aiotools
  from hailtop.utils import periodically_call, secret_alnum_string, time_msecs
  from ...globals import INSTANCE_VERSION, live_instance_states
  from ...instance_config import QuantifiedResource
  from ..instance import Instance
  from ..location import CloudLocationMonitor
  from ..resource_manager import CloudResourceManager, UnknownVMState, VMDoesNotExist, VMStateCreating, VMStateRunning, VMStateTerminated
label_desc: Use image node_id 11 for calling the InstanceCollection obj's underlying member method code with example usage: obj.generate_machine_name() and returns: machine_name