// TLD with a wildcard rule and exceptions.
    checkPublicSuffix("ck", null)
    checkPublicSuffix("test.ck", null)
    checkPublicSuffix("b.test.ck", "b.test.ck")
    checkPublicSuffix("a.b.test.ck", "b.test.ck")
    checkPublicSuffix("www.ck", "www.ck")
    checkPublicSuffix("www.www.ck", "www.ck")
    // US K12.
    checkPublicSuffix("us", null)
    checkPublicSuffix("test.us", "test.us")

PublicSuffixDatabase Àã*.0emm.com *.advisor.ws *.alces.network *.awdev.ca *.azurecontainer.io *.backyards.banzaicloud.io *.banzai.cloud *.bd *.beget.app *.build.run *.builder.code.com *.bzz.dapps.earth *.ck *.cloud.metacentrum.cz *.cloudera.site *.cns.joyent.com *.code.run *.compute-1.amazonaws.com *.compute.amazonaws.com *.compute.amazonaws.com.cn *.compute.estate *.cryptonomic.net *.customer-oci.com *.dapps.earth *.database.run *.dev-builder.code.com *.dev.adobeaemcloud.com *.devcdnaccesso.com...