How To Escape a Mako Variable
To stop Attune from trying to substitute a variable, escape it by enclosing it inside Mako raw text tags. In this example, line 2 will be printed exactly as it is written.
1<%text>
2user=cyrus argv=/usr/lib/cyrus-imapd/deliver -e -r ${sender} -m ${extension} ${user}
3</%text>