code: def get_mars_versions(self) -> List[str]:
      versions = set(
          info.env["mars_version"] for info in self._node_infos.values()
      )
      return list(sorted(versions))
  
file_path: mars/mars/services/cluster/supervisor/node_info.py
imports: import time
  from collections import defaultdict
  from typing import Dict, List, Optional, Set
  from ....None import oscar
  from ....resource import Resource
  from ....typing import BandType
  from ...core import NodeRole
  from ..core import NodeInfo, WatchNotifier, NodeStatus
label_desc: Use image node_id 4 for calling the NodeInfoCollectorActor obj's underlying member method code with example usage: obj.get_mars_versions() and returns: list