def METHOD_NAME(self, ocp, dUdT):
    """
    A private function to obtain the open-circuit potential and
    related standard variables when there is a distribution of particle sizes.
    """
    domain, Domain = self.domain_Domain
    reaction_name = self.reaction_name
    # X-average or broadcast to electrode if necessary
    if ocp.domains["secondary"] != [f"{domain} electrode"]:
        ocp_av = ocp
        ocp = pybamm.SecondaryBroadcast(ocp, f"{domain} electrode")
    else:
        ocp_av = pybamm.x_average(ocp)
    if dUdT.domains["secondary"] != [f"{domain} electrode"]:
        dUdT_av = dUdT
        dUdT = pybamm.SecondaryBroadcast(dUdT, f"{domain} electrode")
    else:
        dUdT_av = pybamm.x_average(dUdT)
    variables = {
        f"{Domain} electrode {reaction_name}"
        "open-circuit potential distribution [V]": ocp,
        f"X-averaged {domain} electrode {reaction_name}"
        "open-circuit potential distribution [V]": ocp_av,
    }
    if self.reaction_name == "":
        variables.update(
            {
                f"{Domain} electrode entropic change "
                "(size-dependent) [V.K-1]": dUdT,
                f"X-averaged {domain} electrode entropic change "
                "(size-dependent) [V.K-1]": dUdT_av,
            }
        )
    return variables