Optional entities

[rob1998]

I was wondering if it's possible to make entities optional. Something like adding a {%if entity_id != undefined} in the blueprint.
I'm using the person popup blueprint, but have some persons without a charging entity. If I just leave them empty the rest of the popup works, but it displays an ugly error.

Tried some things myself for a bit, but couldn't work it out. Might have been stupid and just overlooked the function to check if an entity exists.