is it possible to add a condition statement in .yml file ansible?

I have created a role and a playbook , Now in my playbook , I am defining Ec2 tags such as :

instance_tags: "Name=,bld_env=,server=-"

I also have to make a condition here for bld_env thats suppose if bld_env is "test", add more tags . can you help me out with tagging in case of conditional statement ?