Internal function that is used for generation of the 'MainFiles' notebooks header.

    ----------
    Parameters
    ----------
    notebook_object : notebook object
        Object of "notebook" class where the header will be created.

    notebook_title : None or str
        Title of the Notebook.

    notebook_description : str
        An introductory text to present the Notebook and involve the reader.

def _generate_main_files_header(notebook_object, notebook_title="Notebook Title",
                                notebook_description="Notebook Description"):
    """
    Internal function that is used for generation of the 'MainFiles' notebooks header.

    ----------
    Parameters
    ----------
    notebook_object : notebook object
        Object of "notebook" class where the header will be created.

    notebook_title : None or str
        Title of the Notebook.

    notebook_description : str
        An introductory text to present the Notebook and involve the reader.

    """

    # =================================== Creation of Header =======================================
    header_temp = HEADER_MAIN_FILES.replace("Notebook Title", notebook_title)
    notebook_object["cells"].append(nb.v4.new_markdown_cell(header_temp))

    # ================ Insertion of the div reserved to the Notebook Description ===================
    notebook_object["cells"].append(nb.v4.new_markdown_cell(notebook_description,
                                                            **{"metadata":
                                                               {"tags": ["test"]}}))