efault
    one followed by reversed list of older versions.

    List of versions sorted this way can be used in Depends field.

    :param vrepr: return string represenatations of versions, by default the
        same format is used as in :param:`versions`

    >>> debsorted([(2, 6), (3, 1), (3, 2), (3, 3), (2, 7)])[0] == DEFAULT
    True
    >>> debsorted(('2.4', '3.2', '2.6', '2.7'))[-1]
    (2, 4)
    >>> debsorted(set([(2, 1), (2, 2)]))
    [(2, 2), (2, 1)]
    >>> debsorted([(2, 1), (2, 2)], return_str=True)
    ['2.2', '2.1']
    )	rp