Can't create Node in iApp using variables

Hi! I'm trying to create a Node using iApp with the following simple Implementation:

package require iapp 1.0.0

iapp::template start

set addr 1.1.1.1

iapp::conf create ltm node test { address $addr }

iapp::template stop

But when I create a new Application using this iApp, I receive the following error:

script did not successfully complete: ("$addr" invalid IP address while executing "tmsh::create [string range $args 7 end] " ("create" arm line 1) invoked from within "switch -exact -- [string range $args 0 5] { create { tmsh::create [string range $args 7 end] } modify { tmsh::modify [string r..." (procedure "iapp::conf" line 14) invoked from within "iapp::conf create ltm node test { address $addr }" line:6)

In the other hand, if I use the following Implementation (using an IP, not a variable), it works:

package require iapp 1.0.0

iapp::template start

iapp::conf create ltm node test { address 1.1.1.1 }

iapp::template stop

Is there any cast I must do?

Thanks!