def _stats(self, lambda_):
        mu = 1/(exp(lambda_)-1)
        var = (expm1(-lambda_))**2/exp(-lambda_)
        g1 = 2*cosh(lambda_/2.0)
        g2 = 4+2*cosh(lambda_)
        return mu, var, g1, g2
dataset/ETHPy150Open scipy/scipy/scipy/stats/_discrete_distns.py/planck_gen._stats/swapped operands of `/`