Error while connecting bro with RYU controller

I am a newbie in bro.
I am trying to run bro script which communicated messages to RYU controller.
I just follow instructions on:

Getting this error:
sg5414@controller:/tmp/bro-netcontrol/openflow$ bro -C -i eth0 example.bro
error in ./example.bro, line 18: unknown identifier OpenFlow::broker_new, at or near “OpenFlow::broker_new”

Any help is appreciated.

Sahil Gupta