getting an error when using default(omit)

Hi - i have am trying to use the omit feature with my default

like this

default_availability_zone = {{ cinder_default_availability_zone | default(omit) }}

and i am getting the following error. I am using ansible 1.8.1. Any idea on what i am doing wrong? This seems very simple…

fatal: [192.168.110.173] => {‘msg’: ‘TypeError: do_default() takes at most 3 arguments (4 given)’, ‘failed’: True}

this was a user error. I had something else wrong in my playbook