def METHOD_NAME(
    self, params: QAOAVariationalBaseParams
) -> Tuple[float, float]:
    """
    Compute the expectation value w.r.t the Cost Hamiltonian and its uncertainty
    Parameters
    ----------
    params: `QAOAVariationalBaseParams`
            The QAOA parameters - an object of one of the parameter classes, containing
            variable parameters.
    Returns
    -------
    `Tuple[float]`
            expectation value and its uncertainty of cost operator wrt
            to quantum state produced by QAOA circuit.
    """
    prob_dict = self.probability_dict(params)
    cost = cost_function(
        prob_dict, self.qaoa_descriptor.cost_hamiltonian, self.cvar_alpha
    )
    cost_sq = cost_function(
        prob_dict,
        self.qaoa_descriptor.cost_hamiltonian.hamiltonian_squared,
        self.cvar_alpha,
    )
    uncertainty = np.sqrt(cost_sq - cost**2)
    return (cost, uncertainty)