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

    match = TFORMAT_ASCII_RE.match(tform.strip())
    if (not match):
        raise VerifyError('Format    {!r}    is    not    recognized.'.format(tform))
    format = match.group('format')
    if (format is None):
        format = match.group('formatf').upper()
        width = match.group('widthf')
        precision = match.group('precision')
        if ((width is None) or (precision is None)):
            if strict:
                raise VerifyError('Format    {!r}    is    not    unambiguously    an    ASCII    table    format.')
            else:
                width = (0 if (width is None) else width)
                precision = (1 if (precision is None) else precision)
    else:
        format = format.upper()
        width = match.group('width')
        if (width is None):
            if strict:
                raise VerifyError('Format    {!r}    is    not    unambiguously    an    ASCII    table    format.')
            else:
                width = 0
        precision = 0
    def convert_int(val):
        msg = 'Format    {!r}    is    not    valid--field    width    and    decimal    precision    must    be    integers.'
        try:
            val = int(val)
        except (ValueError, TypeError):
            raise VerifyError(msg.format(tform))
        return val
    if (width and precision):
        (width, precision) = (convert_int(width), convert_int(precision))
    elif width:
        width = convert_int(width)
    else:
        (width, precision) = ASCII_DEFAULT_WIDTHS[format]
    if (width <= 0):
        raise VerifyError('Format    {!r}    not    valid--field    width    must    be    a    positive    integeter.'.format(tform))
    if (precision >= width):
        raise VerifyError("Format    {!r}    not    valid--the    number    of    decimal    digits    must    be    less    than    the    format's    total    width    {}.".format(tform, width))
    return (format, width, precision)

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

def _parse_ascii_tformat(tform, strict=False):