How to use the sphinx.util.osutil.ensuredir function in Sphinx

def configure_backend(app):
    global DEFAULT_CONFIG

    config = copy.deepcopy(DEFAULT_CONFIG)
    config.update(app.config.images_config)
    app.config.images_config = config

    ensuredir(os.path.join(app.env.srcdir, config['cache_path']))

    # html builder
    # self.relfn2path(imguri, docname)

    backend_name_or_callable = config['backend']
    if isinstance(backend_name_or_callable, str):
        try:
            backend = list(pkg_resources.iter_entry_points(
                                group='sphinxcontrib.images.backend',
                                name=backend_name_or_callable))[0]
            backend = backend.load()
        except IndexError:
            raise IndexError("Cannot find sphinxcontrib-images backend "
                                "with name `{}`.".format(backend_name_or_callable))
    elif callable(backend_name_or_callable):
        pass

graphviz_dot = options.get('graphviz_dot', self.builder.config.graphviz_dot)
    hashkey = (code + str(options) + str(graphviz_dot) +
               str(self.builder.config.graphviz_dot_args)).encode('utf-8')

    fname = '%s-%s.%s' % (prefix, sha1(hashkey).hexdigest(), format)
    relfn = posixpath.join(self.builder.imgpath, fname)
    outfn = path.join(self.builder.outdir, self.builder.imagedir, fname)

    if path.isfile(outfn):
        return relfn, outfn

    if (hasattr(self.builder, '_graphviz_warned_dot') and
       self.builder._graphviz_warned_dot.get(graphviz_dot)):
        return None, None

    ensuredir(path.dirname(outfn))

    # graphviz expects UTF-8 by default
    if isinstance(code, text_type):
        code = code.encode('utf-8')

    dot_args = [graphviz_dot]
    dot_args.extend(self.builder.config.graphviz_dot_args)
    dot_args.extend(['-T' + format, '-o' + outfn])
    if format == 'png':
        dot_args.extend(['-Tcmapx', '-o%s.map' % outfn])
    try:
        p = Popen(dot_args, stdout=PIPE, stdin=PIPE, stderr=PIPE)
    except OSError as err:
        if err.errno != ENOENT:   # No such file or directory
            raise
        logger.warning(__('dot command %r cannot be run (needed for graphviz '

try:
            p = Popen(ltx_args, stdout=PIPE, stderr=PIPE)
        except OSError as err:
            if err.errno != ENOENT:   # No such file or directory
                raise
            self.builder.warn('LaTeX command %r cannot be run (needed for math '
                              'display), check the pngmath_latex setting' %
                              self.builder.config.pngmath_latex)
            self.builder._mathpng_warned_latex = True
            return None, None

    stdout, stderr = p.communicate()
    if p.returncode != 0:
        raise MathExtError('latex exited with error', stderr, stdout)

    ensuredir(path.dirname(outfn))
    # use some standard dvipng arguments
    dvipng_args = [self.builder.config.pngmath_dvipng]
    dvipng_args += ['-o', outfn, '-T', 'tight', '-z9']
    # add custom ones from config value
    dvipng_args.extend(self.builder.config.pngmath_dvipng_args)
    if use_preview:
        dvipng_args.append('--depth')
    # last, the input file name
    dvipng_args.append(path.join(tempdir, 'math.dvi'))
    try:
        p = Popen(dvipng_args, stdout=PIPE, stderr=PIPE)
    except OSError as err:
        if err.errno != ENOENT:   # No such file or directory
            raise
        self.builder.warn('dvipng command %r cannot be run (needed for math '
                          'display), check the pngmath_dvipng setting' %

def extract_zip(filename: str, targetdir: str) -> None:
    """Extract zip file to target directory."""
    ensuredir(targetdir)

    with ZipFile(filename) as archive:
        for name in archive.namelist():
            if name.endswith('/'):
                continue
            entry = path.join(targetdir, name)
            ensuredir(path.dirname(entry))
            with open(path.join(entry), 'wb') as fp:
                fp.write(archive.read(name))

except InvokeError:
        self.builder._imgmath_warned_latex = True  # type: ignore
        return None, None

    # .dvi -> .png/.svg
    try:
        if image_format == 'png':
            imgpath, depth = convert_dvi_to_png(dvipath, self.builder)
        elif image_format == 'svg':
            imgpath, depth = convert_dvi_to_svg(dvipath, self.builder)
    except InvokeError:
        self.builder._imgmath_warned_image_translator = True  # type: ignore
        return None, None

    # Move generated image on tempdir to build dir
    ensuredir(path.dirname(outfn))
    shutil.move(imgpath, outfn)

    return relfn, depth

def build_container(self, outdir: str = None, outname: str = 'META-INF/container.xml') -> None:  # NOQA
        """Write the metainfo file META-INF/container.xml."""
        if outdir:
            warnings.warn('The arguments of EpubBuilder.build_container() is deprecated.',
                          RemovedInSphinx40Warning, stacklevel=2)
        else:
            outdir = self.outdir

        logger.info(__('writing %s file...'), outname)
        filename = path.join(outdir, outname)
        ensuredir(path.dirname(filename))
        copy_asset_file(path.join(self.template_dir, 'container.xml'), filename)

def render_plantuml(self, node, fileformat):
    refname, outfname = generate_name(self, node, fileformat)
    if os.path.exists(outfname):
        return refname, outfname  # don't regenerate
    ensuredir(os.path.dirname(outfname))
    f = open(outfname, 'wb')
    try:
        try:
            p = subprocess.Popen(generate_plantuml_args(self, fileformat),
                                 stdout=f, stdin=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
        except OSError as err:
            if err.errno != ENOENT:
                raise
            raise PlantUmlError('plantuml command %r cannot be run'
                                % self.builder.config.plantuml)
        serr = p.communicate(node['uml'].encode('utf-8'))[1]
        if p.returncode != 0:
            raise PlantUmlError('error while running plantuml\n\n' + serr)
        return refname, outfname
    finally:

try:
            p = Popen(ltx_args, stdout=PIPE, stderr=PIPE)
        except OSError as err:
            if err.errno != ENOENT:   # No such file or directory
                raise
            logger.warning('LaTeX command %r cannot be run (needed for math '
                           'display), check the pngmath_latex setting',
                           self.builder.config.pngmath_latex)
            self.builder._mathpng_warned_latex = True
            return None, None

    stdout, stderr = p.communicate()
    if p.returncode != 0:
        raise MathExtError('latex exited with error', stderr, stdout)

    ensuredir(path.dirname(outfn))
    # use some standard dvipng arguments
    dvipng_args = [self.builder.config.pngmath_dvipng]
    dvipng_args += ['-o', outfn, '-T', 'tight', '-z9']
    # add custom ones from config value
    dvipng_args.extend(self.builder.config.pngmath_dvipng_args)
    if use_preview:
        dvipng_args.append('--depth')
    # last, the input file name
    dvipng_args.append(path.join(tempdir, 'math.dvi'))
    try:
        p = Popen(dvipng_args, stdout=PIPE, stderr=PIPE)
    except OSError as err:
        if err.errno != ENOENT:   # No such file or directory
            raise
        logger.warning('dvipng command %r cannot be run (needed for math '
                       'display), check the pngmath_dvipng setting',