Currently I am only able to set the userlists to closed. Is it possible to delete them entirely?
$audience = new \ExpressionRuleUserList();
$audience->id = $audienceId;
$audience->status = 'CLOSED';
$operation = new \UserListOperation();
$operation->operand = $audience;
$operation->operator = 'SET';
$result = $this->audienceService->mutate([$operation]);