Conditional Groovy script ro send an email

[Mithil]

Request is to generate notification to one of our Distribution list  when request is created from portal. I am using "Post function" call "Email issues", this post function is generating an email but I need to set the condition on this post function. And condition needs to set up in groovy expression.

Condition is: When "request-channel-type in (portal)" then generate the notification.

Any suggestion or help!!!