human
Here's a good function header given the following:
I wrote the below code

    global compressor
    compressor = kwargs.pop('compress', None)
    if compressor:
        compressor = u(compressor)
    append = kwargs.pop('append', None)
    if append:
        mode = 'a+b'
    else:
        mode = 'wb'
    def writer(fh):
        for a in args:
            fh.write(pack(a, **kwargs))
    path_or_buf = _stringify_path(path_or_buf)
    if isinstance(path_or_buf, compat.string_types):
        with open(path_or_buf, mode) as fh:
            writer(fh)
    elif (path_or_buf is None):
        buf = compat.BytesIO()
        writer(buf)
        return buf.getvalue()
    else:
        writer(path_or_buf)

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

def to_msgpack(path_or_buf, *args, **kwargs):