def METHOD_NAME(self):
    self.H0_true = 70
    self.omega_m_true = 0.3
    self._ok_true = 0.1
    self.cosmo = FlatLambdaCDM(H0=self.H0_true, Om0=self.omega_m_true, Ob0=0.05)
    self.cosmo_interp = CosmoInterp(cosmo=self.cosmo, z_stop=3, num_interp=100)
    self.cosmo_ok = LambdaCDM(
        H0=self.H0_true,
        Om0=self.omega_m_true,
        Ode0=1.0 - self.omega_m_true - self._ok_true,
    )
    self.cosmo_interp_ok = CosmoInterp(
        cosmo=self.cosmo_ok, z_stop=3, num_interp=100
    )
    self.cosmo_ok_neg = LambdaCDM(
        H0=self.H0_true,
        Om0=self.omega_m_true,
        Ode0=1.0 - self.omega_m_true + self._ok_true,
    )
    self.cosmo_interp_ok_neg = CosmoInterp(
        cosmo=self.cosmo_ok_neg, z_stop=3, num_interp=100
    )
    # input interpolation classes
    z_list = np.linspace(start=0.01, stop=3, num=100)
    ang_dist_list = self.cosmo_ok.angular_diameter_distance(z_list).value
    Ok0 = self.cosmo_ok._Ok0
    dh = self.cosmo_ok._hubble_distance
    K = -Ok0 / dh**2
    self.cosmo_ok_input = CosmoInterp(
        cosmo=None,
        z_stop=None,
        num_interp=None,
        ang_dist_list=ang_dist_list,
        z_list=z_list,
        Ok0=Ok0,
        K=K.value,
    )
    ang_dist_list = self.cosmo_ok_neg.angular_diameter_distance(z_list).value
    Ok0 = self.cosmo_ok_neg._Ok0
    dh = self.cosmo_ok_neg._hubble_distance
    K = -Ok0 / dh**2
    self.cosmo_ok_neg_input = CosmoInterp(
        cosmo=None,
        z_stop=None,
        num_interp=None,
        ang_dist_list=ang_dist_list,
        z_list=z_list,
        Ok0=Ok0,
        K=K.value,
    )