def _pmf(self, x, mu1, mu2):
        px = np.where(x < 0,
                _ncx2_pdf(2*mu2, 2*(1-x), 2*mu1)*2,
                _ncx2_pdf(2*mu1, 2*(1+x), 2*mu2)*2)
        # ncx2.pdf() returns nan's for extremely low probabilities
        return px
dataset/ETHPy150Open scipy/scipy/scipy/stats/_discrete_distns.py/skellam_gen._pmf/original