code: def next_frozen_vm(self):
      if not self.vms:
          self.vms = self.resource_pool.vm
          if len(self.vms) <= 0:
              raise ValueError(
                  f"No vm in resource pool {self.resource_pool.name}!"
              )
      with self.lock:
          logger.debug(
              "current_vm_index=%d",
              self.current_vm_index,
          )
          vm = self.vms[self.current_vm_index]
          self.current_vm_index += 1
          if self.current_vm_index >= len(self.vms):
              self.current_vm_index = 0
      return vm
  
file_path: ray/python/ray/autoscaler/_private/vsphere/scheduler.py
imports: import logging
  import threading
  from enum import Enum
  from pyVmomi import vim
label_desc: Use image node_id 2 for calling the RoundRobinScheduler obj's underlying member method code with example usage: obj.next_frozen_vm() and returns: vm