Snort 2.9.16 Session config flush_on_alert too many parameters error

Snort 2.9.16 Session config flush_on_alert too many parameters error

I saw on the snort manual an setting for the Session global processor called flush_on_alert that I'm interested in. However, when I tried to edit snort.conf to add the setting, I recieved an error upon running snort.

ERROR: /etc/snort/snort.conf(283) => Too many parameters for option in Session config.

I'm confused, as I'm using Snort 2.9.16, and the manual is also written for 2.9.16 any error was unexpected.

http://manual-snort-org.s3-website-us-east-1.amazonaws.com/node17.html#SECTION00322000000000000000