@cache_readonly
def _dispersion_factor(self):
    mu = self.predict(which='linear')
    w = (1 - (self.predict() / np.exp(self.predict(which='linear'))))
    return (1 + (w * np.exp(mu)))
@cache_readonly
def _dispersion_factor(self):
    mu = self.predict(which='linear')
    w = (1 - (self.predict() / np.exp(self.predict(which='linear'))))
    return (1 + (w * np.exp(mu)))