def getz(r, nr):
    z = [2*nr[0]/r[1]]
    for i in xrange(len(nr)-2):
        z.append(2*(r[i+2]-r[i])/nr[i+1])
    z.append(nr[-1]/(r[-1]-r[-2]))
    return z
dataset/ETHPy150Open isnowfy/snownlp/snownlp/utils/good_turing.py/getz/swapped operands of `/`