code: def _warn_on_unsupported_keys(unsupported_keys):
      if unsupported_keys:
          warnings.warn(
              f"The following metadata cannot be exported "
              f"to the text notebook: {sorted(unsupported_keys)}"
          )
  
imports: import logging
  import os
  import sys
  import warnings
  from copy import copy, deepcopy
  import nbformat
  from nbformat.v4.nbbase import NotebookNode, new_code_cell, new_notebook
  from nbformat.v4.rwbase import NotebookReader, NotebookWriter
  from .cell_metadata import _IGNORE_CELL_METADATA
  from .formats import _VALID_FORMAT_OPTIONS, divine_format, format_name_for_ext, get_format_implementation, guess_format, long_form_one_format, read_format_from_metadata, rearrange_jupytext_metadata, update_jupytext_formats_metadata
  from .header import encoding_and_executable, header_to_metadata_and_cell, insert_jupytext_info_and_filter_metadata, insert_or_test_version_number, metadata_and_cell_to_header
  from .languages import default_language_from_metadata_and_ext, set_main_and_cell_language
  from .metadata_filter import filter_metadata, update_metadata_filters
  from .myst import MYST_FORMAT_NAME, myst_extensions, myst_to_notebook, notebook_to_myst
  from .pandoc import md_to_notebook, notebook_to_md
  from .pep8 import pep8_lines_between_cells
  from .quarto import notebook_to_qmd, qmd_to_notebook
  from .version import __version__
label_desc: Use image node_id 7 for calling a global function with example usage: _warn_on_unsupported_keys(unsupported_keys) without return types