code: def release_free_slot(
      self, slot_id: int, session_stid: Tuple[str, str]
  ):
      acquired_session_stid = self._slot_to_session_stid.pop(
          slot_id, None
      )
      if acquired_session_stid is None:
          raise SlotStateError(f"Slot {slot_id} is not acquired.")
      if acquired_session_stid != session_stid:
          raise SlotStateError(
              f"Slot {slot_id} releasing state incorrect, "
              f"the acquired session_stid: {acquired_session_stid}, "
              f"the releasing session_stid: {session_stid}"
          )
      acquired_slot_id = self._session_stid_to_slot.pop(
          acquired_session_stid
      )
      assert (
          acquired_slot_id == slot_id
      ), f"{acquired_session_stid}: acquired_slot_id {acquired_slot_id} != slot_id {slot_id}"
  
      logger.debug("Slot %d released", slot_id)
  
      if slot_id not in self._free_slots:
          self._free_slots.add(slot_id)
          self._semaphore.release()
  
imports: import asyncio
  import logging
  import os
  import time
  from typing import Dict, List, NamedTuple, Set, Tuple
  import psutil
  from ....None import oscar
  from ....oscar.errors import NoFreeSlot, SlotStateError
  from ....oscar.backends.allocate_strategy import IdleLabel
  from ....resource import Resource
  from ....typing import BandType
  from ...cluster import WorkerSlotInfo, ClusterAPI
label_desc: Use image node_id 5 for calling the BandSlotManagerActor obj's underlying member method code with example usage: obj.release_free_slot(slot_id, session_stid) without return types