How to use the impedance.circuits.BaseCircuit function in impedance

self.name = 'Randles w/ CPE'
            self.circuit = 'R0-p(R1,E1)-W1'
        else:
            self.name = 'Randles'
            self.circuit = 'R0-p(R1,C1)-W1'

        circuit_len = calculateCircuitLength(self.circuit)

        assert len(self.initial_guess) + len(self.constants) == circuit_len, \
            'The number of initial guesses + ' + \
            'the number of constants ({})'.format(len(self.initial_guess)) + \
            ' needs to be equal to ' + \
            'the circuit length ({})'.format(circuit_len)


class CustomCircuit(BaseCircuit):
    def __init__(self, circuit, **kwargs):
        """ Constructor for a customizable equivalent circuit model

        Parameters
        ----------
        initial_guess: numpy array
            Initial guess of the circuit values

        circuit: string
            A string that should be interpreted as an equivalent circuit


        Notes
        -----
        A custom circuit is defined as a string comprised of elements in series
        (separated by a `-`) and elements in parallel (grouped as (x,y)).

if conf_x:
                    ax.fill_betweenx(-np.imag(min_Zr), np.real(min_Zr),
                                     np.real(max_Zr), alpha='.2',
                                     color='#7f7f7f', zorder=-2)
                if conf_y:
                    ax.fill_between(np.real(min_Zi), -np.imag(min_Zi),
                                    -np.imag(max_Zi), alpha='.2',
                                    color='#7f7f7f', zorder=-2)

                ax.set_ylim(base_ylim)
                ax.set_xlim(base_xlim)
        return ax


class Randles(BaseCircuit):
    """ A Randles circuit model class """
    def __init__(self, CPE=False, **kwargs):
        """ Constructor for the Randles' circuit class

        Parameters
        ----------
        initial_guess: numpy array
            Initial guess of the circuit values

        CPE: boolean
            Use a constant phase element instead of a capacitor
        """
        super().__init__(**kwargs)

        if CPE:
            self.name = 'Randles w/ CPE'