code: def _default_summary_fmt_factory() -> Optional[str]:
      result: Optional[str] = _default(_Values.SUMMARY_FMT)
      return result
  
imports: import contextlib
  import os
  from dataclasses import dataclass, field, replace
  from typing import Any, Dict, Generator, List, Mapping, Optional, Union
  import numpy
  import tabulate
  import tensorflow
  import tensorflow_probability
label_desc: Use image node_id 9 for calling a global function with example usage: _default_summary_fmt_factory() and returns: result