Optional Input in Blueprints

Hello A54D,
Welcome to the HA forum.

I was going to say something clever like check line 58, but you have not provided any code or what you have tried so far.
Is it possible, well most things are possible. Not all things, but most things.

https://community.home-assistant.io/t/how-to-help-us-help-you-or-how-to-ask-a-good-question.