human
I wrote the below code

    r_files = {'files': [], 'directories': [], 'symlinks': []}
    def _recurse(topdir, rel_offset, parent_dirs, rel_base=u''):
        "\n                                This    is    a    closure    (function    utilizing    variables    from    it's    parent\n                                function's    scope)    so    that    we    only    need    one    copy    of    all    the    containers.\n                                Note    that    this    function    uses    side    effects    (See    the    Variables    used    from\n                                outer    scope).\n\n                                :arg    topdir:    The    directory    we    are    walking    for    files\n                                :arg    rel_offset:    Integer    defining    how    many    characters    to    strip    off    of\n                                                the    beginning    of    a    path\n                                :arg    parent_dirs:    Directories    that    we're    copying    that    this    directory    is    in.\n                                :kwarg    rel_base:    String    to    prepend    to    the    path    after    ``rel_offset``    is\n                                                applied    to    form    the    relative    path.\n\n                                Variables    used    from    the    outer    scope\n                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n\n                                :r_files:    Dictionary    of    files    in    the    hierarchy.        See    the    return    value\n                                                for    :func:`walk`    for    the    structure    of    this    dictionary.\n                                :local_follow:    Read-only    inside    of    :func:`_recurse`.    Whether    to    follow    symlinks\n                                "
        for (base_path, sub_folders, files) in os.walk(topdir):
            for filename in files:
                filepath = os.path.join(base_path, filename)
   ...

What's a good function header?

Here's a good function header?
assistant
#Here's a good function header.

def _walk_dirs(topdir, base_path=None, local_follow=False, trailing_slash_detector=None):