def loglike(self, endog, mu, freq_weights=1, scale=1.):
        r"""
        The log-likelihood function in terms of the fitted mean response.

        Parameters
        ----------
        endog : array-like
            Endogenous response variable
        mu : array-like
            Fitted mean response variable
        freq_weights : array-like
            1d array of frequency weights. The default is 1.
        scale : float, optional
            Not used for the Binomial GLM.

        Returns
        -------
        llf : float
            The value of the loglikelihood function evaluated at
            (endog,mu,freq_weights,scale) as defined below.

        """

        if np.shape(self.n) == () and self.n == 1:
            return scale * np.sum((endog * np.log(mu/(1 - mu) + 1e-200) +
                                   np.log(1 - mu)) * freq_weights)
        else:
            y = endog * self.n  # convert back to successes
            return scale * np.sum((special.gammaln(self.n + 1) -
                                   special.gammaln(y + 1) -
                                   special.gammaln(self.n - y + 1) + y *
                                   np.log(mu/(1 - mu)) + self.n *
                                   np.log(1 - mu)) * freq_weights)