#   Set: pp::colors
  Set: pp::unicode
Proof state:
A : Bool, B : Bool, H : A ∧ B ⊢ A
## Proof state:
no goals
## Proof state:
A : Bool, B : Bool, H : A ∧ B, H1 : A ⊢ B
## Error (line: 15, pos: 9) unknown tactic 'simple2_tac'
## Error (line: 15, pos: 22) invalid 'done' command, proof cannot be produced from this state
Proof state:
A : Bool, B : Bool, H : A ∧ B, H1 : A ⊢ B
## Proof state:
no goals
## Proof state:
A : Bool, B : Bool, H : A ∧ B, H1 : A, H2 : B ⊢ B ∧ A
## Error (line: 18, pos: 0) failed to prove theorem, proof has been aborted
Proof state:
A : Bool, B : Bool, H : A ∧ B, H1 : A, H2 : B ⊢ B ∧ A
# echo command after failure