code: def read_format_from_metadata(text, ext):
      """Return the format of the file, when that information is available from the metadata"""
      metadata = read_metadata(text, ext)
      rearrange_jupytext_metadata(metadata)
      return format_name_for_ext(metadata, ext, explicit_default=False)
  
imports: import os
  import re
  import warnings
  import nbformat
  import yaml
  from .cell_reader import DoublePercentScriptCellReader, HydrogenCellReader, LightScriptCellReader, MarkdownCellReader, RMarkdownCellReader, RScriptCellReader, SphinxGalleryScriptCellReader
  from .cell_to_text import BareScriptCellExporter, DoublePercentCellExporter, HydrogenCellExporter, LightScriptCellExporter, MarkdownCellExporter, RMarkdownCellExporter, RScriptCellExporter, SphinxGalleryCellExporter
  from .header import header_to_metadata_and_cell, insert_or_test_version_number
  from .languages import _COMMENT_CHARS, _SCRIPT_EXTENSIONS, same_language
  from .magics import is_magic
  from .metadata_filter import metadata_filter_as_string
  from .myst import MYST_FORMAT_NAME, is_myst_available, matches_mystnb, myst_extensions, myst_version
  from .pandoc import is_pandoc_available, pandoc_version
  from .stringparser import StringParser
  from .version import __version__
label_desc: Use image node_id 3 for calling a global function with example usage: read_format_from_metadata(text, ext) and returns: format_name_for_ext