def METHOD_NAME(self):
    c_e_n = pybamm.Variable(
        "Negative electrolyte concentration [mol.m-3]",
        domain=["negative electrode"],
    )
    c_e_s = pybamm.Variable(
        "Separator concentration [mol.m-3]", domain=["separator"]
    )
    c_e_p = pybamm.Variable(
        "Positive electrolyte concentration [mol.m-3]",
        domain=["positive electrode"],
    )
    self.c_e = pybamm.concatenation(c_e_n, c_e_s, c_e_p)
    T_n = pybamm.Variable(
        "Negative electrode temperature [K]", domain=["negative electrode"]
    )
    T_s = pybamm.Variable("Separator temperature [K]", domain=["separator"])
    T_p = pybamm.Variable(
        "Positive electrode temperature [K]", domain=["positive electrode"]
    )
    self.T = pybamm.concatenation(T_n, T_s, T_p)
    self.variables = {
        "Negative electrolyte concentration [mol.m-3]": c_e_n,
        "Positive electrolyte concentration [mol.m-3]": c_e_p,
        "Negative electrode temperature [K]": T_n,
        "Positive electrode temperature [K]": T_p,
    }