code: def defaults(cls):
      return dict(
          base_series_preferences=[],
          base_experiment="",
          step_range=[-1, -1],
          is_base_distributed=False,
      )
  
imports: from typing import Any, Dict, List
  from fastapi import Request
  from labml_db import Model, Index
  from labml_db.serializer.pickle import PickleSerializer
  from labml_db.serializer.yaml import YamlSerializer
  from starlette.responses import JSONResponse
  from labml_app import utils
  from labml_app.logger import logger
  from .distributed_metrics import get_merged_dist_metrics_tracking, get_merged_metric_tracking_util
  from .metrics import MetricsAnalysis, get_metrics_tracking_util, mget
  from ..analysis import Analysis
  from ..None import preferences
  from ...db import run
label_desc: Use image node_id 1 for calling the ComparisonPreferences obj's underlying member method code with example usage: obj.defaults(cls) and returns: dict