(motive : Option (Lean.Expr × Lean.Expr × Lean.Expr) → Sort u_1) →
  (x : Option (Lean.Expr × Lean.Expr × Lean.Expr)) →
    ((fst η θ : Lean.Expr) → motive (some (fst, η, θ))) →
      ((x : Option (Lean.Expr × Lean.Expr × Lean.Expr)) → motive x) → motive x