Aucun50 why would you use a $iif for that. an $iif is not needed.
and you should really think about some sort of flood control, and for just pets and the bot's nick within $1- just do

on *:action:$($+(*,pets,*,$me,*)):#:{

so with no flood control

on *:action:$($+(*,pets,*,$me,*)):#: { .timer.purr 1 1 describe # purrrrrr.... purrrrrr.... }

with flood control witch you should use...

on *:action:$($+(*,pets,*,$me,*)):#: { if (!%purrflood) { set -u3 %purrflood on | .timer.purr 1 1 describe # purrrrrr.... purrrrrr.... } }