code: def gen_uid(cls, session_id: str):
      return f"{session_id}_subtask_processor"
  
imports: import asyncio
  import logging
  import sys
  import time
  from collections import defaultdict
  from typing import Any, Dict, List, Optional, Set, Type, Tuple
  from ....None import oscar
  from ....core import ChunkGraph, OperandType, enter_mode, ExecutionError
  from ....core.context import get_context
  from ....core.operand import Fetch, FetchShuffle, execute
  from ....lib.aio import alru_cache
  from ....metrics import Metrics
  from ....optimization.physical import optimize
  from ....serialization import AioSerializer
  from ....typing import BandType, ChunkType
  from ....utils import calc_data_size, get_chunk_key_to_data_keys, get_node_ip_address, lazy_import
  from ...context import ThreadedServiceContext
  from ...meta.api import MetaAPI, WorkerMetaAPI
  from ...session import SessionAPI
  from ...storage import StorageAPI
  from ...task import TaskAPI, task_options
  from ..core import Subtask, SubtaskStatus, SubtaskResult
  from ..utils import iter_input_data_keys, iter_output_data, get_mapper_data_keys
label_desc: Use image node_id 2 for calling the SubtaskProcessorActor obj's underlying member method code with example usage: obj.gen_uid(cls, session_id) and returns: session_id, str