def _stats(self, df):
        mu = sqrt(2)*special.gamma(df/2.0+0.5)/special.gamma(df/2.0)
        mu2 = mu*mu - df
        g1 = (2*mu**3.0 + mu*(1-2*df))/asarray(np.power(mu2, 1.5))
        g2 = 2*df*(1.0-df)-6*mu**4 + 4*mu**2 * (2*df-1)
        g2 /= asarray(mu2**2.0)
        return mu, mu2, g1, g2
dataset/ETHPy150Open scipy/scipy/scipy/stats/_continuous_distns.py/chi_gen._stats/swapped operands of `-`