code: def infer_data_sources(plot_id, config=None):
      y = config.get("y", None)
  
      if isinstance(y, dict):
          sources = list(y.keys())
      else:
          sources = [plot_id]
  
      x = config.get("x", None)
      if isinstance(x, dict):
          sources.append(first(x.keys()))
  
      return ldistinct(source for source in sources)
  
imports: import csv
  import io
  import os
  from collections import defaultdict
  from copy import deepcopy
  from functools import partial
  from multiprocessing import cpu_count
  from typing import TYPE_CHECKING, Any, Callable, Dict, Iterator, List, Optional, Set, Union
  import dpath
  import dpath.options
  from funcy import first, ldistinct, project, reraise
  from dvc.exceptions import DvcException
  from dvc.log import logger
  from dvc.utils import error_handler, errored_revisions
  from dvc.utils.objects import cached_property
  from dvc.utils.serialize import PARSERS, EncodingError
  from dvc.utils.threadpool import ThreadPoolExecutor
  from dvc_render.image import ImageRenderer
label_desc: Use image node_id 7 for calling a global function with example usage: infer_data_sources(plot_id, config) and returns: ldistinct