How to use the nbconvert.MarkdownExporter function in nbconvert

import nbformat
        from nbconvert import MarkdownExporter
        from jinja2 import DictLoader
        from traitlets.config import Config

        c = Config()
        # c.ExtractOutputPreprocessor.extract_output_types = set()
        c.ExtractOutputPreprocessor.output_filename_template = 'images/{unique_key}_{cell_index}_{index}{extension}'
        c.NbConvertBase.display_data_priority = ['application/javascript', 'text/html', 'text/markdown',
                                                 'image/svg+xml', 'text/latex', 'image/png', 'image/jpeg',
                                                 'text/plain']

        nb = nbformat.read(filename, as_version=4)

        dl = DictLoader({'full.tpl': TEMPLATE})
        md_exporter = MarkdownExporter(config=c, extra_loaders=[
                                       dl], template_file='full.tpl')
        (body, resources) = md_exporter.from_notebook_node(nb)

        self.kp_write(body, images={name.split(
            'images/')[1]: data for name, data in resources.get('outputs', {}).items()})

        # Add cleaned ipynb file
        for cell in nb['cells']:
            if cell['cell_type'] == 'code':
                cell['outputs'] = []  # remove output data
                cell['execution_count'] = None  # reset to not executed
        self.kp.write_src(os.path.basename(filename), nbformat.writes(nb))

for filename in filenames:
                if filename.endswith(".ipynb") and os.path.basename(dirpath) != '.ipynb_checkpoints':
                    parentpath = os.path.relpath(dirpath, notebooks)
                    nb = nbf.read(
                        open(os.path.join(dirpath, filename), 'r'), as_version=4)
                    if rst or all:
                        # EXPORT RST
                        exporter = nbc.RSTExporter()
                        dir = os.path.join(project_root, RST_DIR, parentpath)
                        logging.info("Converting the "+filename +
                                     " notebook to an RST format.")
                        _export(nb, exporter, project_root, dir,
                                parentpath, filename, '.rst')
                    if markdown or all:
                        # EXPORT Markdown
                        exporter = nbc.MarkdownExporter()
                        dir = os.path.join(project_root, DOCS_DIR, parentpath)
                        logging.info("Converting the "+filename +
                                     " notebook to an Markdown format.")
                        _export(nb, exporter, project_root, dir,
                                parentpath, filename, '.md')
                    if script or all:
                        # EXPORT SCRIPT
                        exporter = nbc.ScriptExporter()
                        dir = os.path.join(
                            project_root, SCRIPTS_DIR, parentpath)
                        logging.info("Converting the "+filename +
                                     " notebook to a python script.")
                        _export(nb, exporter, project_root, dir,
                                parentpath, filename, '.py')

                elif filename.endswith(".Rmd"):

Returns: hugo-formatted markdown

    """
    # first, update the notebook's metadata
    update_notebook_metadata(path)

    with open(Path(path)) as fp:
        notebook = nbformat.read(fp, as_version=4)
        assert 'front-matter' in notebook['metadata'], "You must have a front-matter field in the notebook's metadata"
        front_matter_dict = dict(notebook['metadata']['front-matter'])
        front_matter = json.dumps(front_matter_dict, indent=2)

    c = Config()
    c.MarkdownExporter.preprocessors = [CustomPreprocessor]
    markdown_exporter = MarkdownExporter(config=c)

    markdown, _ = markdown_exporter.from_notebook_node(notebook)
    doctored_md = doctor(markdown)
    # added  comment to prevent summary creation
    output = '\n'.join(('---', front_matter, '---', '', doctored_md))

    return output

def display_run_notebook(filename):
    """the display function for running a notebook"""
    import nbconvert
    print("\nNotebook output:")
    
    output = nbconvert.exporters.export(nbconvert.MarkdownExporter(), filename)[0]
    print(output)