∀ {K : Type u_1} {Γ : K → Type u_2} {Λ : Type u_3} {σ : Type u_4} [inst : DecidableEq K] (M : Λ → Turing.TM2.Stmt Γ Λ σ)
  (var : σ) (stk : (k : K) → List (Γ k)), Turing.TM2.step M { l := none, var := var, stk := stk } = none