def ln(label):
    """Draw a 70-char-wide divider, with label in the middle.

    >>> ln('hello there')
    '---------------------------- hello there -----------------------------'
    """
    label_len = len(label) + 2
    chunk = (70 - label_len) // 2
    out = '%s %s %s' % ('-' * chunk, label, '-' * chunk)
    pad = 70 - len(out)
    if pad > 0:
        out = out + ('-' * pad)
    return out
Draw a 70-char-wide divider, with label in the middle.

    >>> ln('hello there')
    '---------------------------- hello there -----------------------------'