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

    (path_or_buf, _, _) = get_filepath_or_buffer(path_or_buf)
    if iterator:
        return Iterator(path_or_buf)
    def read(fh):
        l = list(unpack(fh, encoding=encoding, **kwargs))
        if (len(l) == 1):
            return l[0]
        return l
    if isinstance(path_or_buf, compat.string_types):
        try:
            exists = os.path.exists(path_or_buf)
        except (TypeError, ValueError):
            exists = False
        if exists:
            with open(path_or_buf, 'rb') as fh:
                return read(fh)
    if isinstance(path_or_buf, compat.binary_type):
        fh = None
        try:
            fh = compat.BytesIO(path_or_buf)
            return read(fh)
        finally:
            if (fh is not None):
                fh.close()
    if (hasattr(path_or_buf, 'read') and compat.callable(path_or_buf.read)):
        return read(path_or_buf)
    raise ValueError('path_or_buf    needs    to    be    a    string    file    path    or    file-like')

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

def read_msgpack(path_or_buf, encoding='utf-8', iterator=False, **kwargs):