code: def get_worker_name(self, worker_id: str):
      return {"worker_name": f"UNITTEST_MOCK_{worker_id}"}
  
imports: import unittest
  from typing import Any, Dict, List
  from parlai.crowdsourcing.utils.analysis import AbstractResultsCompiler
  from collections import defaultdict
label_desc: Use image node_id 3 for calling the MockMephistoDB obj's underlying member method code with example usage: obj.get_worker_name(worker_id) and returns: dict