Fails to prove Dummett's formula

[joom]

~$ wang --sequent "[] |- [(a -> b)|(b -> a)]" --backend Text
Before: [] ⊢ [((a) ⊃ (b)) ∨ ((b) ⊃ (a))]
Rule:   OrRight
-------------------
Before: [] ⊢ [(a) ⊃ (b),(b) ⊃ (a)]
Rule:   ImpliesRight
-------------------
End.
This cannot be proved.

(reported by @joseph-vidal-rosset)

[joseph-vidal-rosset]

Independently of this incompleteness of your prover, this is a very nice work.