python实现数字转换为汉字大写

def convert(num):
    ch_num=['零','壹','贰','叁','肆','伍','陆','柒','捌','玖','拾']
    s_unit=['','拾','佰','仟']
    b_unit=['','万', '亿', '兆', '京', '垓', '秭', '穣', '沟', '涧', '正', '载', '极', ['恒河沙'], ['阿僧祇'], ['那由他'], ['不可思议'], ['无量大数']]

    numlist = list(map(int,str(num)))
    numlist.reverse()
    l=[]
    j=0
    for i in range(0, len(numlist), 4):
        p=[]
        if sum(numlist[i:i+4]):
            for ii in range(0, 4):             
                if (i+ii)<len(numlist):
                    if numlist[i+ii]:
                        p.append([s_unit[ii],ch_num[numlist[i+ii]]])
                    else:
                        if p and p[-1] != ['零']:
                            p.append(['零'])
            if j < len(b_unit):
                l.append([b_unit[j]]+p)
            else:
                return "数字太大,超出计量范围！！"
        else:
            if l and l[-1]!=['零'] and l[-1][-1]!=['零']:
                l.append(['零'])
        j += 1
    l = [c for a in l for b in a for c in b if c]
    l.reverse()
    l=''.join(l)
    return l