Create replication slot options

I am testing out some streaming logical replication commands and am having
trouble specifying options when calling CREATE_REPLICATION_SLOT
<https://www.postgresql.org/docs/current/protocol-replication.html#PROTOCOL-REPLICATION-CREATE-REPLICATION-SLOT>
.

I connect to the database with
psql "dbname=replication_test_db replication=database"

Then I am able to successfully run
CREATE_REPLICATION_SLOT test_slot LOGICAL pgoutput;

But if I try to specify the snapshot option with
CREATE_REPLICATION_SLOT test_slot_2 LOGICAL pgoutput SNAPSHOT 'nothing';
the command fails with "ERROR: syntax error"

I have tried several combinations of brackets commas and equals signs but
have not been able to get the command with additional options to work. What
is the right syntax to use here?

Thanks,
Phillip