def containment_angle_bin(self, egy_bins, fraction=0.68, scale_fn=None):
        """Evaluate the PSF containment angle averaged over energy bins."""

        vals = self.interp_bin(egy_bins, self.dtheta, scale_fn=scale_fn)
        dtheta = np.radians(self.dtheta[:, np.newaxis] * np.ones(vals.shape))
        return self._calc_containment(dtheta, vals, fraction)
Evaluate the PSF containment angle averaged over energy bins.