Python | ハイフンで範囲を示した数をリストに展開する

def expand_numbers(s, nmin=1, nmax=100):
    a = []
    for v in re.split('[\s,]+', s):
        if '-' in v:
            v0, v1 = v.split('-')[:2]
            if v0 == '': v0 = nmin
            if v1 == '': v1 = nmax
            a.extend(range(int(v0), int(v1)+1))
        else:
            a.append(int(v))
    return list(set(a))

>>> expand_numbers('3,5,7-10')
[3, 5, 7, 8, 9, 10]

>>> expand_numbers('-5,8')
[1, 2, 3, 4, 5, 8]

>>> expand_numbers('3-5,4-7')
[3, 4, 5, 6, 7]