[unfin] Nimber Addition Code

def nimAdd(a,b):

    def nimSieve(a,b):
        return cache(a,b)

    cch = dict()

    apad = list()
    bpad = list()
    for i in range(a):
        apad.append(nimSieve(i,b))
    for i in range(b):
        bpad.append(nimSieve(a,i))
    return mex(apad + bpad)

    def cache(a,b):
        cch = dict()
        try:
            return cch[spell(a,b)]
        except:
            return write(a,b)

    def write(a,b):
        cch[spell(a,b)] = nimAdd(a,b)

    def spell(a,b):
        return str(a)+","+str(b)

    def mex(S):
        for s in range(max(S)+2 if S else 1):
            if s in S:
                continue
            else:
                return s