def iter_navbars():
    for prev_nb, nb, next_nb in prev_this_next(iter_notebooks()):
        navbar = NAV_COMMENT
        if prev_nb:
            navbar += PREV_TEMPLATE.format(title=get_notebook_title(prev_nb),
                                           url=prev_nb)
        navbar += CONTENTS
        if next_nb:
            navbar += NEXT_TEMPLATE.format(title=get_notebook_title(next_nb),
                                           url=next_nb)
        yield os.path.join(NOTEBOOK_DIR, nb), navbar
def iter_navbars():
    for prev_nb, nb, next_nb in prev_this_next(iter_notebooks()):
        navbar = NAV_COMMENT
        if prev_nb:
            navbar += PREV_TEMPLATE.format(title=get_notebook_title(prev_nb),
                                           url=prev_nb)
        navbar += CONTENTS
        if next_nb:
            navbar += NEXT_TEMPLATE.format(title=get_notebook_title(next_nb),
                                           url=next_nb)
        yield os.path.join(NOTEBOOK_DIR, nb), navbar