[standalone@localhost:9990 /] /subsystem=singleton/singleton-policy=foo/election-policy=random:add{allow-resource-service-restart=true
{"outcome" => "success"}
[standalone@localhost:9990 /] /subsystem=singleton/singleton-policy=foo/election-policy=simple:add{allow-resource-service-restart=true
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0436: Cannot register capability 'org.wildfly.clustering.singleton.policy.election.foo' at location '[
    (\"subsystem\" => \"singleton\"),
    (\"singleton-policy\" => \"foo\"),
    (\"election-policy\" => \"simple\")
]' as it is already registered in context 'global' at location(s) '[[
    (\"subsystem\" => \"singleton\"),
    (\"singleton-policy\" => \"foo\"),
    (\"election-policy\" => \"random\")
]]'",
    "rolled-back" => true
}