protected Map<String, List<Object>> getPrincipalAttributesForPrincipal(final Collection<Authentication> authentications,
                                                                           final Principal principal,
                                                                           final Map<String, List<Object>> principalAttributes) {
        return principalAttributes;
    }
This is {@link DefaultPrincipalElectionStrategy} that selects the primary principal
to be the first principal in the chain of authentication history.

@author Misagh Moayyed
@since 4.2.0
core/cas-server-core-authentication-api/src/main/java/org/apereo/cas/authentication/principal/DefaultPrincipalElectionStrategy.java