The documentation for the api uses the example:
But when using this option and value it produces the following error:
String "allow_once": value not one of declared Enum instance names: [ALLOW, DENY, ALLOW_ONCE]
Lowercase versions of parameters should still be valid unless they are proper names for repository names. But since this is an enum, allow_once should equal ALLOW_ONCE. Both should be converted to lowercase and then compared.