∀ {α : Type u_1} [inst : Group α] {s t : Subgroup α} (h_le : s ≤ t) (f : α ⧸ t → α)
  (hf : Function.RightInverse f QuotientGroup.mk),
  Subgroup.quotientEquivProdOfLE' h_le f hf =
    { toFun := fun a => (Quotient.map' id ⋯ a, Quotient.map' (fun g => ⟨(f (Quotient.mk'' g))⁻¹ * g, ⋯⟩) ⋯ a),
      invFun := fun a => Quotient.map' (fun b => f a.1 * ↑b) ⋯ a.2, left_inv := ⋯, right_inv := ⋯ }