docs: def _check_config():
      """Create config files as necessary."""
      config.CONFIG_DIR.mkdir(parents=True, exist_ok=True)
      verfile = config.CONFIG_DIR / '.version'
      uptodate = verfile.is_file() and verfile.read_text() == __version__
      if not uptodate:
          verfile.write_text(__version__)
      if not (uptodate and config.CONFIG_FILE.is_file()):
          conf.create_config_(update=True)
      for stfile in ('stagpy-paper.mplstyle',
                     'stagpy-slides.mplstyle'):
          stfile_conf = config.CONFIG_DIR / stfile
          if not (uptodate and stfile_conf.is_file()):
              stfile_local = pathlib.Path(__file__).parent / stfile
              shutil.copy(str(stfile_local), str(stfile_conf))