Content Expression for "doc can have 0 or 1 h1 blocks"

1

I found it straightforward to port our doc constraints to the 0.7.0 content expression format.

We would like a new constraint, that a doc can have 0 or 1 h1 blocks (but not >1). How do we define that?

2

Sounds like the question mark operator should cover that – "h1?"