code: def __init__(self) -> None:
      self._data = dict()
      db = MockMephistoDB()
      for idx in range(LEN_MOCK_DATA):
          unit = MockUnit.get(db, "mock_db", defaultdict(int))
          self._data[unit] = {
              "unit_id": idx * 10,
              "worker_id": idx,
              "worker_name": db.get_worker_name(idx),
              "data": {
                  "dialogue": [
                      f"mock dialogue round {i} for unit {idx}"
                      for i in range(4)
                  ]
              },
          }
  
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 1 to create a new MockMephistoBrowser object  with example: obj = MockMephistoBrowser()