class_docstr: Should be in format {config_name: {**config_params}}.
class_docstr_tok: ["Should","be","in","format","{","config_name",":","{","*","*","config_params","}","}","."]
code: def get_default_config_name(self) -> Optional[str]:
      default_config_name = None
      for config_name, metadata_config in self.items():
          if config_name == "default" or metadata_config.get("default"):
              if default_config_name is None:
                  default_config_name = config_name
              else:
                  raise ValueError(
                      f"Dataset has several default configs: '{default_config_name}' and '{config_name}'."
                  )
      return default_config_name
  
imports: import textwrap
  from collections import Counter
  from itertools import groupby
  from operator import itemgetter
  from pathlib import Path
  from typing import Any, ClassVar, Dict, List, Optional, Tuple, Union
  import yaml
  from huggingface_hub import DatasetCardData
  from ..config import METADATA_CONFIGS_FIELD
  from ..info import DatasetInfo, DatasetInfosDict
  from ..utils.logging import get_logger
  from .deprecation_utils import deprecated
label_desc: Use image node_id 5 for calling the MetadataConfigs obj's underlying member method code with example usage: obj.get_default_config_name() and returns: default_config_name