How to use hostnames with hyphens as classes

From Cfwiki

How to set per-server variables if the server name contains a dash:

Dash is automatically converted to underscore in CFengine, so put the hostname with an underscore in it instead of dash.

For example, your hostname is: happy-cow

Use:

   happy_cow::  myvariable = ( "value" )
 

and it'll work.